fix #10822: add "local" options to omero.fs.repo.path_rules

Make sure that the Blitz unit tests `FilePathRestrictionsTest` and `MakePathComponentSafeTest` still pass.

Try using `local required` and `local optional` in `etc/omero.properties` for `omero.fs.repo.path_rules` (remember `./build.py update-version` before restarting the server; you know if your changes are being taken because if you put a nonsense setting then there will be a stack trace in `Blitz-0.log`). These should limit sanitization of import paths according to the machine upon which the server is running.

To see the extra log message from `CurrentPlatform` you may have to adjust levels in `logback.xml`.

To understand the path sanitization rules see http://www.openmicroscopy.org/site/support/omero5-staging/sysadmins/fs-upload-configuration.html#legal-file-names

Fixes https://trac.openmicroscopy.org.uk/ome/ticket/10822.
--no-rebase as FS-specific.