Android: Add Ti.Media.requestPhotoGalleryPermissions() support

Summary:
We should add the following methods on Android for parity with iOS...

• Ti.Media.requestPhotoGalleryPermissions()
• Ti.Media.hasPhotoGalleryPermissions()

Functionality:
On Android 9 and below, these methods should check if the app has WRITE_EXTERNAL_STORAGE permission.

On Android 10 and above, these methods should always return true since we do not need write permission to save a photo/video to the gallery once TIMOB-28059 has been implemented. Google documents this here...
https://developer.android.com/training/camera/photobasics#TaskPath

Note:
Currently, Titanium app developers must use the Ti.Filesystem.requestStoragePermissions() and Ti.Filesystem.hasStoragePermissions() methods before saving to the gallery. This is okay, but we don't need to check for WRITE_EXTERNAL_STORAGE permission on Android 10 and above when saving to the gallery. We also don't want to change the Ti.Filesystem.requestStoragePermissions() method's implementation since it's still needed in case you want to write to other locations on external storage.