Registry: add support for versioned ncbi_taxonomy DBs + improve support for versioned metadata DBs

Created by: mkszuba

Description

Extend the Registry so that it can detect taxonomy databases whose names contain the release number, with backward compatibility with unversioned databases but preference for versioned ones if both forms are present.

Additionally, add several bits of support for versioned metadata databases which failed to make it into #379.

Use case

Starting with release 100 taxonomy databases in Ensembl will have been renamed from ncbi_taxonomy to ncbi_taxonomy_XY, where XY is the release number.

Our support for versioned metadata databases has been incomplete: on the one hand we did not include them in version checks, on the other they were not filtered out by certain methods which did filter out unversioned DBs.

Benefits

Meet the requirements of ENSINT-312. Fewer bugs in support for versioned metadata DBs.

Possible Drawbacks

A slight increase in computational overhead in the Registry, primarily during initialisation. Note that much of this overhead stems from the fact we retain for the time being backward compatibility with the old naming convention, i.e. will eventually go away.

Testing

Have you added/modified unit tests to test the changes?

No, the affected code is tied with specific database names and as such will not trigger for MultiTestDB databases.

If so, do the tests pass/fail?

N/A

Have you run the entire test suite and no regression was detected?

Yes, no regression detected.