block using the Change Repository blob store task

The Admin - Change repository blob store task presently has issues with how it logs what it does (NEXUS-26974) and also risks losing customer data (NEXUS-29084). These problems exist regardless of the database backend used.

Further it has been observed if using OrientDB and it has any duplicate records or corrupt indexes (risks of using that database, and end user may not be aware this issue is present), the task has been shown to leave behind some blobs in the source blobstore without any indication of ERROR or WARN it has done so.

Expected

Due to these risks, prevent the task from being run at all, until at least the above issues are resolved against that database. Provide an advanced configuration option to re-enable it again, to be used only in emergency situations or when the admin user is willing to accept the risks of the known issues.

Other A/C

• Documentation updated to include a message to discourage the use of this task