Provide an internal service for creating and managing an external repository synchronization entry in the journal table

The (enterprise repository replication service uses the repository clustering journal to check and 'replay' changes in the repository for export to an external repository.
The 'point in time' of the last replicated change is therefore based upon and dependent on the entries in the journal.

For the repository cluster synchronization itself, once a change has been synchronized between (all) cluster nodes, the old journal entries no longer are needed.

For the cleanup of the journal, the repository provides an optional configurable automated process, or can be done with a simple sql statement on the backend database directly.

However such cleanup only takes the cluster synchronization itself into account: not an external repository synchronization, like replication, which might be running 'behind' for example if replication has been temporarily disabled.

To ensure that the default repository journal cleanup process and/or a direct sql statement for cleanup is not truncating entries still needed by the external repository synchronization process, a new service will be added which can store and update an external repository synchronization revision id in the LOCAL_REVISION database table.

This will then ensure that the standard/automated truncation of the journal table will take this external repository synchronization revision id as lowest boundary to keep.