feat(android): switch to new callback-style permission requests

[carlpoole]

Changes

• PluginState enum replaces raw strings representing the state of a permission
• Permission response codes are no longer necessary and have been removed
• Behavior run after permission grant/deny is defined in a callback method.
• Permission callback methods are defined on the plugin class with the signature format private void myPermissionCallback(PluginCall, Map<String, PluginState>)
• PluginMethods that result in permission request calls must specify the name of a callback method in the @PluginMethod annotation, for example: @PluginMethod(permissionCallback = "myPermissionCallback")
• The permissionCallback annotation element is important in registering the permission callback in the Activity lifecycle and ensuring the code is run after permission is granted/denied.

2.x

• For backwards compatibility with 2.x, any plugins defined with a permission response code in a @NativePlugin annotation will be handled first before delegating the permission handling to Android for the new callback method.