Hotseat: Allow customization of the app drawer button icon

Change-Id: Ic0904cafdd80c57851df9193eee6569cd4a2ae17
Hotseat: Add a check to make sure we're granted storage permission

Change-Id: Ib230256edf62cdfbc63bd33a6d24e45da1464d29
Use a persistent Uri for app drawer button image, remove system permission

Change-Id: Ief3007dd0e8f7992b0c685df3c55c566fdeb14f8