Add Metadata Explorer OMVS and external identifiers to Automated Curation OMVS

[mandy-chessell]

Description

This PR includes a number of changes:

• There are new search methods in Metadata Explorer OMVS. This provides a comprehensive search facility for open metadata.
• There are new methods in Automated Curation OMVS to both maintain and query information about external identifiers from third parties and their associated open metadata elements.
• The Asset Manager OMAS methods for managing external identifiers have been removed and Asset Manager now uses the governance action framework methods
• The governance action framework methods for managing external identifiers now consistently support effectivity dates, forLineage and forDuplicateProcessing.
• Many of the iterators have been removed from the generic handlers so that paging information passes directly from the external caller to the underlying repositories. (The iterators always started from 0 and discarded anything retrieved up to the startFrom. This meant that paging through large collections was inefficient.)

Related Issue(s)

One of the FVTs from Governance Server OMVS that manages deduplication is no longer working - it is commented out and will be addressed in a future PR.

Testing

Basic regression test. The aim is to make the new OMVS function available to allow the pyegeria functions to be built. The real testing will happen through pyegeria.

Release Notes & Documentation

Descriptions of Metadata Explorer OMVS are in place. Wrok still needs to be don on the external identifiers documentation for Automated Curation OMVS.

Additional notes

None