make it possible to complete the initialization process from outside the metabase.core namespace and trigger it in our test setup process so that logins work for unit tests again.

fix issue where unit test causes setup-token to be recreated on namespace reload, which is annoying in dev.

streamline public settings availability and syncing.  this is driven mostly by the need to have an `:email_configured` property that we can use on the frontend to dictate some of our UI.

add dynamic password complexity checking to the UserStep.  this is done by adding an /api/util/password_check endpoint that we can use to test passwords against as the user puts them in.

tidy up the DatabaseStep and add in full form validation support along with the ability to use the setup api to validate the connection details of possible new database creation.

update revision api tests so that they are focused on testing the endpoint functionality and not a bunch of other stuff.

flush out the unit tests for `(process-revision-event ...)` function which handles new events related to revision tracking.

upgrade the revisions code to work off our new events system so that we can remove some unnecessary code from our api endpoint implementations.

also, included here is a small tweak to the revision model to add a new field/column for :is_creation which is true when we know the revision represents the time when the object was created.

a couple small tweaks to our activity unit tests to prevent race conditions which intermittently cause test failures.