[Java][JVM] Move java specific import mappers to JVM specific code gen (#7569)

* Move java specific import mappers to java specific code gen

* Use JVM specific import mappers in kotlin, scala, groovy

* Update generators docs

* Add autogenerated files

samples/server/petstore/php-laravel/lib/app/Models/File.php

@@ -0,0 +1,15 @@
+<?php
+/**
+ * File
+ */
+namespace app\Models;
+
+/**
+ * File
+ */
+class File {
+
+    /** @var string $sourceURI Test capitalization*/
+    private $sourceURI;
+
+}

samples/server/petstore/php-laravel/lib/app/Models/ModelList.php

@@ -0,0 +1,15 @@
+<?php
+/**
+ * ModelList
+ */
+namespace app\Models;
+
+/**
+ * ModelList
+ */
+class ModelList {
+
+    /** @var string $_123list */
+    private $_123list;
+
+}