length restriction for repositories

for non-hashed repositories we are seeing errors where gitlab allows long repository names that are failing stat call which i assume is failing the 255 byte limit for xfs.

see https://sentry.gitlap.com/gitlab/gitlabcom/issues/135698/

We should probably visit length limit enforcement for non-hashed storage and possibly hashed-storage as well if we currently do not have any enforcement. We should probably have a good understanding of other limits as well (branch names for example) if we don't already.