Introduce rtc_test_suite and rtc_cc_test 

rtc_cc_test represents a single test or a small collection of tests. It
generates both an rtc_library to be included in an rtc_test or
rtc_test_suite, as well as a standalone rtc_test to run those few tests.

rtc_test_suite represents a collection of tests and produces a binary
containing all tests.

An action is added to confirm that an rtc_cc_test is included in an
rtc_test_suite. If this is not the case, one may not compile the
standalone test binary for the unit test.

These new templates will replace the monolithic rtc_test/rtc_library
to allow for faster test execution. 

Bug: webrtc:498394143
Change-Id: Id3fb3108449bd9c73bc0e7f674d7a97f6a6a6964
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/461480
Reviewed-by: Jeremy Leconte <jleconte@google.com>
Commit-Queue: Evan Shrubsole <eshr@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47352}