Add the themes configuration entry point

Change-Id: I0eb669956d9e89bb92cd43487b14b4246454a400
Signed-off-by: ayysir <dresadd09691@gmail.com>

Conflicts:
	res/values/strings.xml
	res/xml/settings_headers.xml

(cherry picked from commit efabf079e7a6be2bb4fcd5a7f5875f2714663c6c)

Conflicts:
	res/xml/settings_headers.xml
Derp