ensure that all hashers are supported by the server (rebased from dev_5_0)

Check that `etc/omero.properties` lists all hashers among `omero.checksum.supported` and that the managed repository unit tests pass (see `testAllChecksumAlgorithmsProvided`, `testAllChecksumAlgorithmsSupported`).

--rebased-from #2850
--depends-on #2847