Allow disabling the Options Pannel feature for TVs

- Added a config entry in velues-television to disable the options panel
feature for TVs.
- Fixed parts of the code in PhoneWindow that assumed this feature is supposed
to always be available, which was causing exceptions when it was turned off.

Bug: 18780696
Change-Id: I923bd4b5019d634e5352a6e893005133edb475f6