Improve VTS: Allow Extra Filters for Live and Playback

This CL allows vendors to specify extra filters they would like to
include in the Live dataflow. Note, however, that these filters are not
included in any integration tests yet, as those will come later.

Additionally, this CL cleans up the code originally used to configure
extra filters for DVR playback. It converts the code and API strucutre
to a uniform format consistent with that of other dataflows that allow
extra filters.

Bug: b/239751563

Test: vts-tradefed run vts --module VtsHalTvTunerTargetTest
Change-Id: I662814666873254eff84791b5057da1f44f5e73e