ums: support UMS on any volume

Change-Id: I43668a5200d30cef953e0d3e9ded2d8cf0cbbd22
Vectone UK (MNC01) considered non-roaming on T-Mobile (MNC30)

Change-Id: Id74c854f958be721be12451a124cfd2f8b150255
Crop wallpaper and lockscreen images before saving them

Images were saved as-is and could cause large heap usage when
Wallpaper loads them later. This patch crop the images to fit the
screen size before saving them (as wallappper cropper activity does)

Change-Id: I08c04d9d14a65355c4417f0414d7a6ac538b3ea0