Add parameters to specify custom native build path and enable unity build in Android gradle builds (#1494)

* Add parameters to specify custom native build path and enable unity build in Android gradle builds

* Enable unity build for gradle to shorten the path to the generated object files which fixes build failures on Jenkins due to paths exceeding limit. This also speeds up builds.

cmake/Tools/Platform/Android/generate_android_project.py

@@ -215,6 +215,11 @@ def main(args):
                         default=None,
                         required=False)
 
+    parser.add_argument('--native-build-path',
+                        help='Custom path to place native build artifacts.',
+                        default=None,
+                        required=False)
+
     # Asset Options
     parser.add_argument(INCLUDE_APK_ASSETS_ARGUMENT_NAME,
                         action='store_true',
@@ -258,6 +263,10 @@ def main(args):
                         action='store_true',
                         help='Option to overwrite existing scripts in the target build folder if they exist already.')
 
+    parser.add_argument('--enable-unity-build',
+                        action='store_true',
+                        help='Enable unity build')
+
     parsed_args = parser.parse_args(args)
     wrap_parsed_args(parsed_args)
 
@@ -395,7 +404,9 @@ def main(args):
                                                         asset_type=parsed_args.get_argument(ASSET_TYPE_ARGUMENT_NAME),
                                                         signing_config=signing_config,
                                                         is_test_project=is_test_project,
-                                                        overwrite_existing=parsed_args.overwrite_existing)
+                                                        overwrite_existing=parsed_args.overwrite_existing,
+                                                        unity_build_enabled=parsed_args.enable_unity_build,
+                                                        native_build_path=parsed_args.native_build_path)
     generator.execute()