Task #10811: radb.py: use db table resource_monitoring.resource_usage for method getResourceUsages. adapted code using getResourceUsages.

Task #10339: added refresh button, so users can force the du cache to be refreshed (for the current task/project) themselves.

Fix merge conflict on momqueryservice.py. Moved on trunk, but changed on this branch.
Solve by replacing the moved file with the changed file (thus, move the changed file over the moved file).
Careful checking of (JD's) changes shows this is correct; the changes are preserved.
Other moved files did not cause conflicts, since they were not changed.

Task #10339: use factory method to get either a fast direct radb connection per thread, or get the default radb RPC connection. This improves loading times dramatically.

Task #10057: import _strptime solves a random python AttributeError when converting strings to datetime in a multitreaded environment

Task #10057: show pin icons for tasks with pinned data. Allow users to pin/unpin task data via webscheduler

Task #9931 #10057: merged feature branch ^/branches/ltaingest-Task9931 into LOFAR-Release-2_19 branch