BPDS: create db schema and migration code

[wayne-weibel]

We will be implementing a separate tracking table for submission to BPDS (and Lighthouse). Create a schema diagram that will allow tracking any claim sent to any service, with standard date/time columns, encrypted 'metadata', encrypted 'payload', and status.

This does (and should) not be a copy of FormSubmission and FormSubmissionAttempt

Once diagram is complete/approved, create the db migration files necessary.