Improve Tuner VTS: Generate Descrambling Combos

This CL allows the VTS to read a vendor's configuration file, determine
if the given devices could support the Descrambling dataflow, and generate
all combinations of units to run them on corresponding integration tests.
Each combination is error checked to ensure they meet the minumum
requirements, and any invalid ones are discared, which may narrow the
combination space immensely.

Bug: b/182519645

Test: vts-tradefed run vts --module VtsHalTvTunerTargetTest. Manual
tests with different input configuration files.

Change-Id: Ic1b9dae6b43f8f01bc4e490ef9e910a933562bd2