TMSS-152: refactored observation task->subtask specification conversion, so it's more generic, and easier to read.

TMSS-152: added test_create_task_blueprints_and_subtasks_subtasks_from_scheduling_unit_draft_with_UC1_requirements

TMSS-152: made sure that create_task_drafts_from_scheduling_unit_draft is always called when processing specification in scheduling_unit_draft. Check and skip already created task_drafts and/or relations

TMSS-189: create UC1 SchedulingUnit with a whole task grapsh specified in json conform the scheduling-unit-schema (based on Roy's example data in the t_tasks test)

TMSS-189: return fields sorted alphabetically, with id and url first so it's easy to identify and 'click' them

TMSS-152: Calculate start time using previous observation subtask info and time_offset specified in the scheduling_relation. Also use duration from task specification to calculate stop time

TMSS-189: made seperate methods for populating cycles and projects. removed example TaskDrafts, and made/called example SchedulingUnit

TMSS-189: removed scheduling part from these draft->blueprint tests, because 1) scheduling just is not part of draft->blueprint conversion, and 2) now that RA is part of scheduling, it would require additional RA test setup. See t_scheduling for actual scheduling tests.

TMSS-152: Create also SchedulingRelationBlueprint of SchedulingRelationDraft during draft-to-blueprint. Fix in name test data for rest api.

TMSS-152: use same related names of task scheduling relation draft/blueprint as currently delivered with TMSS-50 in master