SystemUI: QuietHours Shortcut

Enables QuietHours to be toggled via
    other applications

PS2: Big AOSP guidelines rework
PS3: Forgot to rename class
PS4: Ribbons Class in same package
    Was already using "QuietHoursToggle"
    So a rename was required

Change-Id: I5797b7aba834f0f219683e8a5acc3eabde15aa8c