Remove the option to support JDK7 from Java generator and templates (#11547)

* remove java8 from java client generator and templates

* update tests

* remove threetenbp

* update spring templates to remove java8

* remove java8 from jaxrs template

* fix jaxrs spec

* fix feign

* remove CustomInstantDeserializer.java

* fix jersey1

* fix undertow

* various update

* fix jaxrs jersey1

* fix java inflector

* fix jaxrs cxf

* add new files

* update doc

samples/client/petstore/java/okhttp-gson-dynamicOperations/build.gradle

@@ -117,7 +117,6 @@ dependencies {
     implementation 'org.openapitools:jackson-databind-nullable:0.2.1'
     implementation group: 'org.apache.oltu.oauth2', name: 'org.apache.oltu.oauth2.client', version: '1.0.1'
     implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.10'
-    implementation 'org.threeten:threetenbp:1.4.3'
     implementation 'io.swagger.parser.v3:swagger-parser-v3:2.0.23'
     implementation "jakarta.annotation:jakarta.annotation-api:$jakarta_annotation_version"
     testImplementation 'junit:junit:4.13.1'