Force Show Vector Drawables (UnifiedEmail)

Added anydpi-v21 drawable folder, which causes the system
to prioritize the xmls in the folder and use them over
the ones in xxhdpi for xxxhdpi devices.

Also removed unnecessary xxxhdpi icons and updated notif
mail and multiple_mail icons.

Removed three files from the vector drawable folder as we
cannot call BitmapFactory.decodeResources(...) on vector
drawables:
- ic_star_outline_20dp
- ic_star_20dp
- ic_check_wht_24dp
We will have to go back and change how we initialize the
bitmaps from the vector drawables later. These have been
recorded in the bug.

Finally, updated notification and parent folder icons.

Bug: 17936539
Change-Id: If7759b47824a06aadd4ec038cb6ab7fb8e5fdfe3
103 files changed