Normalize plate names in Cellvoyager converter

[jluethi]

Let's improve our strategy for plate name of the OME-Zarrs. We want to avoid some special characters like # (see fractal-analytics-platform/fractal-vizarr-viewer#33). We should also drop other potentially weird characters from plate names.

We still want to support _ and - though.
And we need to harmonize this with our plate name uniqueness check

[tcompa]

In case it's useful, we have a couple of sanitize/validate auxiliary functions in fractal-server which may be similar to what could be used here - see https://github.com/fractal-analytics-platform/fractal-server/blob/032367f69e292065f451c45e4c11614727e63b6f/fractal_server/string_tools.py.