Re-architect how Android plugins are packaged and handled at export time

The previous packaging format for Godot Android plugins consisted of the plugin's `gdap` config file accompanied by binaries defined in the `gdap` file.
This format is now deprecated (starting with Godot 4.2), and instead Godot Android plugins are now packaged as `EditorExportPlugin` plugins.

The `EditorExportPlugin` class has been updated with the following methods to provide the necessary set of functionality:
- `_supports_platform`: returns true if the plugin supports the given platform
- `_get_android_dependencies`: retrieve the set of android dependencies (e.g: `org.godot.example:my-plugin:0.0.0`) provided by the plugin
- `_get_android_dependencies_maven_repos`: retrieve the urls of the maven repos for the provided android dependencies
- `_get_android_libraries`: retrieve the local paths of the android libraries (AAR files) provided by the plugin
- `_get_android_manifest_activity_element_contents`: update the contents of the `<activity>` element in the generated Android manifest
- `_get_android_manifest_application_element_contents`: update the contents of the `<application>` element in the generated Android manifest
- `_get_android_manifest_element_contents`: update the contents of the `<manifest>` element in the generated Android manifest

doc/classes/EditorPlugin.xml

@@ -569,6 +569,12 @@
 				Returns the [PopupMenu] under [b]Scene > Export As...[/b].
 			</description>
 		</method>
+		<method name="get_plugin_version" qualifiers="const">
+			<return type="String" />
+			<description>
+				Provide the version of the plugin declared in the [code]plugin.cfg[/code] config file.
+			</description>
+		</method>
 		<method name="get_script_create_dialog">
 			<return type="ScriptCreateDialog" />
 			<description>