[kotlin][client] Add Jackson to interface properties and remove extra line feed (#5459)

* [kotlin][client] Ensure Jackson annotations are consistent with interface vars

* [kotlin][client] Rebuild samples

* [kotlin][client] Some kotlin client enhancements

- Don't use JsonFormat for Date objects, this should be controlled via
  a custom serializer/deserializer or a turning on and off serialization
  features of Jackson.  I've updated the jacksonObjectMapper config to
  write the dates as strings, which I think was intended in the original
  commit.
  https://fasterxml.github.io/jackson-databind/javadoc/2.6/com/fasterxml/jackson/databind/SerializationFeature.html#WRITE_DATES_AS_TIMESTAMPS
  https://fasterxml.github.io/jackson-databind/javadoc/2.6/com/fasterxml/jackson/databind/cfg/MapperConfig.html#getDateFormat--
- Dont' use @JsonFormat(shape = JsonFormat.Shape.OBJECT) for enums.
  This causes Enums to be formatted as objects with an internal "value"
  field.  In reality, OpenAPI enums are just strings without properties
  and should be treated as a string.
  https://www.baeldung.com/jackson-serialize-enums#2-enum-as-json-object
- Add's Kotlin use site annotation @get: to JsonProperty for parent interface
  properties.  Otherwise Kotlin will warn:
  "This annotation is not applicable to target 'member property without
  backing field or delegate'"
- Add's JsonTypeInfo annotations to interfaces for inheritance.  This
  was copied verbatim from the kotlin-spring generator.
  https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/kotlin-spring/typeInfoAnnotation.mustache

* [kotlin][client] Rebuild kotlin samples

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/ApiResponse.kt

@@ -23,14 +23,11 @@ import java.io.Serializable
 
 data class ApiResponse (
     @Json(name = "code")
-    val code: kotlin.Int? = null
-,
+    val code: kotlin.Int? = null,
     @Json(name = "type")
-    val type: kotlin.String? = null
-,
+    val type: kotlin.String? = null,
     @Json(name = "message")
     val message: kotlin.String? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/Category.kt

@@ -22,11 +22,9 @@ import java.io.Serializable
 
 data class Category (
     @Json(name = "id")
-    val id: kotlin.Long? = null
-,
+    val id: kotlin.Long? = null,
     @Json(name = "name")
     val name: kotlin.String? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/Order.kt

@@ -26,24 +26,18 @@ import java.io.Serializable
 
 data class Order (
     @Json(name = "id")
-    val id: kotlin.Long? = null
-,
+    val id: kotlin.Long? = null,
     @Json(name = "petId")
-    val petId: kotlin.Long? = null
-,
+    val petId: kotlin.Long? = null,
     @Json(name = "quantity")
-    val quantity: kotlin.Int? = null
-,
+    val quantity: kotlin.Int? = null,
     @Json(name = "shipDate")
-    val shipDate: kotlin.String? = null
-,
+    val shipDate: kotlin.String? = null,
     /* Order Status */
     @Json(name = "status")
-    val status: Order.Status? = null
-,
+    val status: Order.Status? = null,
     @Json(name = "complete")
     val complete: kotlin.Boolean? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123
@@ -54,7 +48,6 @@ data class Order (
     * Values: placed,approved,delivered
     */
     
-    
     enum class Status(val value: kotlin.String){
         @Json(name = "placed") placed("placed"),
         @Json(name = "approved") approved("approved"),

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/Pet.kt

@@ -28,24 +28,18 @@ import java.io.Serializable
 
 data class Pet (
     @Json(name = "id")
-    val id: kotlin.Long? = null
-,
+    val id: kotlin.Long? = null,
     @Json(name = "category")
-    val category: Category? = null
-,
+    val category: Category? = null,
     @Json(name = "name")
-    val name: kotlin.String
-,
+    val name: kotlin.String,
     @Json(name = "photoUrls")
-    val photoUrls: kotlin.Array<kotlin.String>
-,
+    val photoUrls: kotlin.Array<kotlin.String>,
     @Json(name = "tags")
-    val tags: kotlin.Array<Tag>? = null
-,
+    val tags: kotlin.Array<Tag>? = null,
     /* pet status in the store */
     @Json(name = "status")
     val status: Pet.Status? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123
@@ -56,7 +50,6 @@ data class Pet (
     * Values: available,pending,sold
     */
     
-    
     enum class Status(val value: kotlin.String){
         @Json(name = "available") available("available"),
         @Json(name = "pending") pending("pending"),

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/Tag.kt

@@ -22,11 +22,9 @@ import java.io.Serializable
 
 data class Tag (
     @Json(name = "id")
-    val id: kotlin.Long? = null
-,
+    val id: kotlin.Long? = null,
     @Json(name = "name")
     val name: kotlin.String? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123

samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/models/User.kt

@@ -28,30 +28,22 @@ import java.io.Serializable
 
 data class User (
     @Json(name = "id")
-    val id: kotlin.Long? = null
-,
+    val id: kotlin.Long? = null,
     @Json(name = "username")
-    val username: kotlin.String? = null
-,
+    val username: kotlin.String? = null,
     @Json(name = "firstName")
-    val firstName: kotlin.String? = null
-,
+    val firstName: kotlin.String? = null,
     @Json(name = "lastName")
-    val lastName: kotlin.String? = null
-,
+    val lastName: kotlin.String? = null,
     @Json(name = "email")
-    val email: kotlin.String? = null
-,
+    val email: kotlin.String? = null,
     @Json(name = "password")
-    val password: kotlin.String? = null
-,
+    val password: kotlin.String? = null,
     @Json(name = "phone")
-    val phone: kotlin.String? = null
-,
+    val phone: kotlin.String? = null,
     /* User Status */
     @Json(name = "userStatus")
     val userStatus: kotlin.Int? = null
-
 ) : Serializable {
 	companion object {
 		private const val serialVersionUID: Long = 123