frameworks: add persistent notification when USB OTG is connected

Tapping the notification will take the user into Storage settings, and
highlight the 'Unmount' option.

Change-Id: I650f3874a8295b2b8ffdaef78aff4b68e9cd574e
Signed-off-by: Roman Birg <roman@cyngn.com>
derp
Merge remote-tracking branch 'upstream/cm-11.0' into cm-11.0