TMSS-215: added action url to create a new SchedulingUnit based on this SchedulingUnitObservingStrategyTemplate, with the given <name> and <description> and make it a child of the given <scheduling_set_id>

TMSS-215: added foreignkeys between SchedulingUnitObservingStrategyTemplate and SchedulingUnitDraft and SchedulingUnitTemplate, and added JSON validation for SchedulingUnitObservingStrategyTemplate and if the SchedulingUnitDraft was created from a SchedulingUnitObservingStrategyTemplate

Resolve TMSS-281

Closes TMSS-281

See merge request !195

Resolve TMSS-266

Closes TMSS-266

See merge request !193

Resolve TMSS-239

Closes TMSS-239

See merge request !196

TMSS-215: replaced code-wise generation of UC1 scheduling unit with the use of the new UC1 observation strategy template

TMSS-215: filled in schema names. TODO: need to replace those with proper URI's (URL's) once TMSS-272 is done and we have URL's for those schema's

TMSS-215: replaced 'data-flow' sorting by predecessor recursion because python sort does not work with proper compare functions anymore, but with key functions which address each item in the list only once O(N) while we are interested in the inter-item-relations O(N.N-1)

TMSS-239: Moved TriggerEmailService one level up to resolve build issue after merging master to TMSS-239 as per Auke's instruction.

# Conflicts:
#	SAS/TMSS/frontend/tmss_webapp/package.json
#	SAS/TMSS/frontend/tmss_webapp/src/App.css
#	SAS/TMSS/frontend/tmss_webapp/src/App.js
#	SAS/TMSS/frontend/tmss_webapp/src/components/ViewTable.js
#	SAS/TMSS/frontend/tmss_webapp/src/layout/sass/_viewtable.scss
#	SAS/TMSS/frontend/tmss_webapp/src/routes/Project/create.js
#	SAS/TMSS/frontend/tmss_webapp/src/routes/Project/edit.js
#	SAS/TMSS/frontend/tmss_webapp/src/routes/Scheduling/SchedulingUnitList.js
#	SAS/TMSS/frontend/tmss_webapp/src/routes/index.js
#	SAS/TMSS/frontend/tmss_webapp/src/services/cycle.service.js
#	SAS/TMSS/frontend/tmss_webapp/src/services/project.service.js
#	SAS/TMSS/frontend/tmss_webapp/src/services/schedule.service.js
#	SAS/TMSS/frontend/tmss_webapp/src/utils/unit.converter.js

Resolved All Conflicts

TMSS-239: Header Column Size Adjusted, Unit Conversion Code reduced, few state properties moved to class properties.

Resolve TMSS-280

Closes TMSS-280

See merge request !192

TMSS-215: fixed typo in filter. Add defaults to given task_specifications_doc if needed, so the user can upload subset specs and trust that all defaults are filled in.

TMSS-215: added _populate_scheduling_unit_observation_strategry_schema, and adapted populate code for scheduling unit for new schema

TMSS-215: added observation strategy template for UC1 from https://support.astron.nl/jira/browse/TMSS-215. references to templates still need to be filled in.

TMSS-215: added model SchedulingUnitObservingStrategyTemplate which will hold templates describing observation stratefies for schedulingunits based on referenced SchedulingUnitTemplates

Resolve TMSS-243

Closes TMSS-243 and TMSS-294

See merge request !191

Changes updated