SW-699: adaptations to new rpc.py module. Not fully finished yet for all datamanagement services and rpcs

SW-699: Make notifications unconfigurable, greatly reducing complexity of the higher abstraction layers.

SW-699: Use a single broker and bus (exchange), and make service names unconfigurable (fixed in Service and RPC). Greatly reduces configuration size.

SW-448: keep copy of current cache_timestamp update estimated path_cache_result in cache, and (re)set the cache_timestamp to the old one, so it will be picked up for a later real du scan

SW-448: update cache entries from bottem to top in dir tree. do fast summation first, and slow du later.

ROHD-692: only persist the most important subset of the cache to disk, because (de)serialization of large dicts is just too slow and memomy consuming

Task #11188: performance boost in writing cache to disk. Side effect: speeds up scheduling and webscheduler

Task #11090: keep results for unknown paths in cache as well, so we can return them quickly as well.

Task #9939: RA: CleanupService and StorageQueryService: fix resource selection by name from 'cep4' to 'CEP4' in accordance with changed CEP4 resource names in radb many commits earlier in this branch

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.