add test names to pick to the -s cmdline option
When picking individual tests to run, we have the same test names across all suites.
Semantically each suite should have its own set of test names.
With argparse, we can't figure out which -t option came in-between which -s options, and also to confuse the users less, we should change the cmdline arg -s to include the test names in the suite:scenarios scheme like:
-s sms:sysmo -s sms:sysmo+aoip:mo_mt_sms -s debug::fail
(and maybe replace '+' with ',' or allow both -- the one adds requirements, the other lists items, but for the user it's just a separating character and easy to forget which is which)
This way it is also possible to add specific test names to the default-suites.conf