feat(migrations-bundle): add bundle to manage migrations

[echocrow]

could be a special bundle like files, with the main goal of running a series of "up" commands, continuing since the last ran "up" function

TBD:

• API (likely a bunch of specially named functions? hello good ol' drupal 7 days...)
• tracking latest migration step (git-ignored file in repo? a dedicated file in ~/.local/state?