Settings: Allow access for external apps to launch ThemeSettings Fragment directly

Change-Id: I93b676d3eb570c7064eeb4217c8e420a186c8e32
Settings: add TEME_SETTINGS intent and SHORTCUT category to
ThemeSettings intent

Change-Id: Ie5d8c401adc612502ff1db27fa4861a27d876a41
Signed-off-by: Roman Birg <roman@cyngn.com>