TMSS-697: Add scheduling contraints to SU blueprint, copy from draft on creation, prevent update in non-schedulable state.

TMSS-715: Update check for default piggyback values propagation, only for objects in the 'creating' state

TMSS-666: removed set_subtask_state_following_allowed_transitions from subtasks.py. It was moved in TMSS-725 to test_utils.py

TMSS-64: profile -> pulsar profile to be more explicit and clear. no need is foreseen to ever mix pulsar profiles with other profiles

TMSS-64: Parset keys for dataproduct lists are now generated by a function, removing a lot of code duplication.

TMSS-725: processed review comment: split the ERROR state into (generic)ERROR and UNSCHEDULABLE which are both end-states.

TMSS-725: processed review comment. moved set_subtask_state_following_allowed_transitions into test_utils so that it is clearly intended to be used in tests only, and not in normal tmss code. Took the opportunity to move the TMSSTestEnvironment into its own module as well to make a clear distinction between test-helper-methods (in test_utils.py) and the TMSSTestEnvironment (in test_environment.py). Adapted all tests with new import paths.