Only supported command is list (strun is not supported)

[braingram]

It's currently possible to run:

python -m stpipe list

due to ListCommand being included in the _COMMAND_CLASSES:

stpipe/src/stpipe/cli/main.py

Lines 16 to 18 in 370e104

	_COMMAND_CLASSES = [
	ListCommand,
	]

However no "run" command is supported making

python -m stpipe strun ...

unsupported (which would be useful in situations where pdb is used via python -m pdb -m stpipe strun ...).