Task #9939: assigner, RAtoOTDB propagator: address Auke's review comments + a few small cleanups of my own

Task #10801: Fixed indentations, added test for invalid root_resource_group, fixed test for RCUs, fixed duplicate test names

Task #10801: Remove task from findClaims and helper functions, and add tests for findClaims/fitSingleResources/fitMultipleResources

Task #10801: Moved db_resource_prop_types, db_storage_type_id, db_rcu_type_id, db_rgp2rgp, db_resource_types to (cached) properties to avoid excessive propagation of function arguments that are actually fixed values.

Task #10784: Renamed claim status "claimed" (ID 0) to "tentative" and claim status "allocated" (ID 1) to "claimed" in both Python code and  database creation/allocation scripts. Successfully verified that all unit tests that originally passed still pass, and that those that originally didn't pass, don't give new errors.

Task #9939: RA assigner: add comments to clarify warning wrt not finding predecessor and successor to link to in radb

Task #9939: RA: re-enable some unit tests in t_resourceassigner and remove some others no longer useful. Also fix error path bug in assigner and ensure assigner code coverage reports uncovered line list of ResourceAssigner modules. This commit supplements r37300. All regression tests now pass (without disabling any test).

Task #9939: RA: rework estimator format to fix predecessor issues with calibration pipeline. Also adjust and much better document other estimators. Small adjustment to assigner wrt properties. This prepares for more testing on the test sys, so this commit likely contains brown paper bugs.

Task #9939: RA: adjust estimator pipelines to new estimator format. Also minor adjustments to assigner prop handling. Tests still to fix.

Task #10695: Removed Observation.Scheduler.taskDuration, added a timestamp parser function to PyCommon, and do not silently fail on unparsable startTime/stopTime in paret.

Task #10560: Fixed t_resourceassigner again, after it got broken during sprint 5 integration (for demo).

Task #10560: Implemented a suggestion for a is_claimable_rcu_wise() function. Needs to be discussed though if this is the way to go

Task #10560: No functional changes, a bit of refactoring and an attempt to implement the is_claimable() functionality for RCUs

Task #10560: Enabled all resource_assigner tests again and added unittest for added functionality. Code-coverage=85%

Task #10560: Added functionality for adding RCU capacity to the claims, and added functionality for storing the  RCU bit patterns to the RADB. Please, mind the TODOs!!!

Task #9939: RA assigner: restore logic to also (check specs and) insert task if status is approved. Patch by Adriaan Renting.

Task #10560: After discussion with Alexander removed checking on existence output_files, and added some docstrings

Task #9939: RA: after talking with Jorrit about this, remove comment from assigner again about storage claim duration post-obs. You cannot update available_capacity, since it's derived, not stored.