Aperture: Improve vendor extensions handling

* Make getSupportedModes a ExtensionsManager method
* Always set supportedExtensionModes, we can query them regardless of the camera mode
* Restore extensionModeIndex as well (fixes wrong icon on app reopening)

Change-Id: I6ffca1c56f4ab23b5c2cb8f31d1e5d82bb1f9c3b
3 files changed