Deprecate edx-platform `paver update_db`

[robrap]

paver update_db is an old way of running migrations for edxapp, but doesn't work in devstack and should just be removed. See openedx/edx-platform#32252 for more details.

A/C:

• DEPR update_db
• make migrate runs migrations in the current environment
• Remove references to using update_db everywhere (doc, github workflow?)

Notes:

• Any existing devstack calls (e.g. in docs) should be changed to make dev.migrate.lms+studio
• The reference in devstack is commented out as of this commit: 4e83604 (may want to see why before deleting it?)
• 2U: See private https://twou.slack.com/archives/C04A66RDPEZ/p1686068124202099?thread_ts=1686067860.936839&cid=C04A66RDPEZ for recent incident of this issue.
• The ticket openedx/edx-platform#32252 can be closed once this is completed.

[dianakhuang]

DEPR ticket created: openedx/edx-platform#32683