Add command to permanently migrate GMs

[beatngu13]

Just like in the legacy retest CLI, we need something like a migrate command to permanently migrate Golden Masters. Is there something comparable in Git (CC @martin-v), otherwise maybe:

# Migrates all GMs.
recheck migrate

# Migrate all GMs from test suite.
recheck migrate src/test/resources/retest/recheck/my.company.RecheckTest

# Migrate specific GM.
recheck migrate src/test/resources/retest/recheck/my.company.RecheckTest/testCase.checkpoint.recheck

We also need something comparable in review.

[beatngu13]

See #121 and discussion.

[martin-v]

@kema91 the task is mostly done (see #121), but the integration test is missing, can you add this please, thx.

[beatngu13]

migrate command is hidden until we have a proper integration test: 0282c45