Docker Autotest: New control file example

Because everybody seems to want moe controw!

This one accepts the legacy ``--args=<csv,list,of,subtests>`` but adds two more space-separated options ``i=<csv,list,to,include>`` and ``x=<csv,list,to,exclude>``.  It also introduces a control-specific configuration file ``control.ini``.  Command-line options are combined with options in the control configuration file then the whole lot is written back out into the Autotest ``results`` directory for later reference (including by subtests if needed).

If this looks good, the next step is to extend the ``SubSubtestCaller`` class to read ``<self.job.resultdir> / control.ini`` and **NOT** load any sub-subtest module that's not also listed in the ``subtests`` configuration option.  This is the key to how we avoid needing to raise TestNaError for skipping tests.

Now, the coolest part (IMHO, and thanks to JC), this will also allows us to tag both subtests *and* sub-subtests with certain "blocker" bugzillas.  If those bugs are open and not fixed, those tests will automatically skip (i.e. not load).  Of course this feature can be disabled.