[SMS Plugin] Adding mms support to KDE Connect mobile app

Adding MMS support to the android app

Note: After merging this MR, MR 274 for KDE Connect C++ repository must be merged to maintain the compatibility.

To be able to send MMS on android the app should be set as a default app.

This patch enables the user to set KDE Connect as the default SMS app on their device if the user wants to send MMS through the desktop client.

Test Plan

Deploy the app on your android device.

Set it as default SMS app in the optional permissions in the main UI.

You can receive and send SMS and MMS from the notification in the status bar.