TMSS-190: do not check for dynamic_scheduling_enable here (but let the responsibility in the dynamic_scheduler)

TMSS-190: renamed Setting AUTOSCHEDULE/allow_scheduling_observations to DYNAMIC_SCHEDULING_ENABLED/dynamic_scheduling_enabled. Disabled it by default for TMSS as requested by PO. Enabled it for the test environment if the dynamic scheduler service is started.

TMSS-259: Change format according to Jan Davids suggestions. Change list input to tuples and add caching.

TMSS-259: Add tests for angular separation endpoint. Improve speed on sunrise endpoint by reducing precision.

TMSS-259: Remove optional slash and api_view again from /schemas/ and /station_groups/ because it breaks json ref resolution and more

TMSS-459: Add new endpoint 'angular_separation_from_bodies' and backend logic to calculate distance of a pointing from solar system bodies

TMSS-190: processed review comments. Added documentation. Removed implicit parameters(=None). Factored out slabs of code into simple functions.

TMSS-190: let stoptime be set by client(s) instead of assuming that a state update to finishing should always set the subtaks's stoptime

TMSS-435: Return json object with sunrise, sunset, day and night times at sun_rise_and_set call, handle multiple stations and timestamps provided as parameters

TMSS-190: removed obsolete method calculate_start_time. Added SubtaskSchedulingException when the duration is less then 1 second.

TMSS-322: reimplemented this feature. As stated in the ticket: such a convenience log_url is not part of the Subtask model, but can be a view on the model. So, implemeted it in the viewset. Now, fetching subtasks from the TMSS db is superfast again.

(cherry picked from commit 3bec3e06)

TMSS-190: and TMSS-388: only enable viewflow if TMSS_ENABLE_VIEWFLOW envvar is set, or if --viewflow option is given

TMSS-403: Improvement: use build/installed TMSS settings module and LOFARROOT for static files and templates so that django toolbar and frontend work out of the box