add astropy Table support to compare_asdf

[braingram]

tweakreg_catalog is now stored as an astropy.table.Table. This PR adds astropy.table.Table support to compare_asdf to allow regression tests to compare any Table instances (including tweakreg_catalog). This should fix tests that are failing with a reported difference that includes the unprocessed key (indicating that a portion of the items to being compared could not be processed due to lack of support for Table comparisons).

Regression tests all passed: https://plwishmaster.stsci.edu:8081/job/RT/job/Roman-Developers-Pull-Requests/393/

Checklist

• added entry in CHANGES.rst under the corresponding subsection
• updated relevant tests
• updated relevant documentation
• updated relevant milestone(s)
• added relevant label(s)
• ran regression tests, post a link to the Jenkins job below. How to run regression tests on a PR

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Files	Coverage Δ
romancal/regtest/regtestdata.py	63.47% <100.00%> (+2.05%)	⬆️

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[mairanteodoro]

Looking good to me. Thanks, @braingram!