Allow to pass extra arguments

Environment named named csstudio as it's shared with CS-Studio (no need
to have separate environments).
And Phoebus is still CS-Studio (just a new version).

JIRA INFRA-1428 #action In Progress

The script needs more modifications to set the variables required for
the local Python environment.
We don't really have to use the phoebus.sh script that comes with the
release (it doesn't contain much).

Allow to start phoebus from the command line as well.

JIRA INFRA-1428