Cleanup instance.clid

Instances CLID are all stored in the same folder; default-domain/connectRoot/instances folder; growing more and more which is today one of our slowest query.

We don't need anymore most of the CLID, and an easy way to do increase performance would be to remove not used ones. When a CLID is used to access NOS; a metadata connectinstance:lastAccessDate is updated.

We could leverage that field to delete CLID not accessed for 1 year.

SELECT * FROM ConnectInstance WHERE connectinstance:lastAccessDate <= DATE '2019-09-30'