PEEK: configurable pickup timeout (1/2)

- Allow the user to set different pickup timeout when a notification comes up through PEEK.

Change-Id: Ifcd2f13101dcf6973ebcf016bce5f5314e1ce04c
PEEK pick up timeout: ensure stock value on clean install and also show summary of it (1/2)

- This commit fix a derp where Settings.Secure is called and not the right one: Settings.System
- Inlcude a settings observer for futures ideas

Change-Id: Ic449ada65820cb6c73a7867d1d287f837c37c221