Updating TrfTestsART to the recommended conditionstags + other updates, 9.8.2021

This MR makes the following updates for the TrfTestsART tests:

• enabling these tests in branch 22.0-mc20 using # art-include: 22.0-mc20/Athena (this has no effect currently; the tests will be enabled after the new branch 22.0-mc20 is synchronized with master)
• update to the recommended conditions tags: CONDBR2-BLKPA-RUN2-06 and OFLCOND-MC16-SDR-RUN2-08
• change of the 21.0 version for RDOtoRDOtrigger 21.0.129 (it was 21.0.126) in MC tests

Tagging @rmazini @elmsheus