[DRAFT] Implement migrations cli command

[lutzmor]

Guide doc: http://localhost:8081/guide/migrations/

Migrations should be executable from the cli by jumping up into the server shell via the vantage command.

• migrations should be defined in a directory, referenced by a migration service
• On login to remote cli, migrations should be checked and notified to the console whether or not any need to be run
• Command to run migration should default to dry run, outputting the raw sql, OR run in transaction and user must confirm to commit (probably easier to implement).
• Use prompt to confirm the dry run, then execute