[kotlin-client][kotlin-server] feature: allow creation of kotlin data classes that implement java.io.Serializable (#3997)

* feat: allow creation of kotlin data classes that implement java.io.Serializable, by adding the config option serializableModel=(true|false)

* docs: add markdown docu for new configOption serializableModel

* fix: do not use parcelize in script

* update kotlin samples

* add the option, update the doc

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

@@ -13,6 +13,7 @@ package org.openapitools.client.models
 
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * Describes the result of uploading an image resource
  * @param code 
@@ -27,5 +28,7 @@ data class ApiResponse (
     val type: kotlin.String? = null,
     @Json(name = "message")
     val message: kotlin.String? = null
-)
+) 
+: Serializable 
+
 

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

@@ -13,6 +13,7 @@ package org.openapitools.client.models
 
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * A category for a pet
  * @param id 
@@ -24,5 +25,7 @@ data class Category (
     val id: kotlin.Long? = null,
     @Json(name = "name")
     val name: kotlin.String? = null
-)
+) 
+: Serializable 
+
 

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

@@ -13,6 +13,7 @@ package org.openapitools.client.models
 
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * An order for a pets from the pet store
  * @param id 
@@ -37,7 +38,9 @@ data class Order (
     val status: Order.Status? = null,
     @Json(name = "complete")
     val complete: kotlin.Boolean? = null
-)
+) 
+: Serializable 
+
 {
 
     /**

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

@@ -15,6 +15,7 @@ import org.openapitools.client.models.Category
 import org.openapitools.client.models.Tag
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * A pet for sale in the pet store
  * @param id 
@@ -39,7 +40,9 @@ data class Pet (
     /* pet status in the store */
     @Json(name = "status")
     val status: Pet.Status? = null
-)
+) 
+: Serializable 
+
 {
 
     /**

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

@@ -13,6 +13,7 @@ package org.openapitools.client.models
 
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * A tag for a pet
  * @param id 
@@ -24,5 +25,7 @@ data class Tag (
     val id: kotlin.Long? = null,
     @Json(name = "name")
     val name: kotlin.String? = null
-)
+) 
+: Serializable 
+
 

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

@@ -13,6 +13,7 @@ package org.openapitools.client.models
 
 
 import com.squareup.moshi.Json
+import java.io.Serializable
 /**
  * A User who is purchasing from the pet store
  * @param id 
@@ -43,5 +44,7 @@ data class User (
     /* User Status */
     @Json(name = "userStatus")
     val userStatus: kotlin.Int? = null
-)
+) 
+: Serializable 
+