Improve Sentry diagnostic information

[Gudahtt]

Recently we've seen some confusing Sentry error reports, which seem to indicate that migrations have run successfully but the state remains in the pre-migration state. Currently the Sentry error reports don't provide enough information to determine what is happening here. We are going to improve the diagnostic information sent to Sentry to help investigate this problem.

• Log when migrations are happening
  • Log within migrator what the current migration version is, and which pending migrations we are running
• Log and report to Sentry when an invariant is unmet in a migration
  • For each branch in a migration where we bail, we should either console.log (for anticipated scenarios) or captureException (for impossible scenarios)
  • We should update migrations back to first recent network controller state change
• Log state shape to Sentry
  • Log state shape just to top-level controller state properties, including just the type of any properties omitted by mask
  • In background, update to use non-flatted state
• Log migration version to Sentry
  • Update getSentryState to include current migration version
  • This version would be stored in appState controller or in new application metadata controller
• Validate versioned data after running migrations
  • Includes improving existing validation (we check for falsy state)
• Log current and previous app version
  • New application metadata controller
• Ensure Sentry mask is up-to-date
  • Consider building mask dynamically using metadata for newer controllers, with hard-coded mask remaining for older controllers
  • Edit: Postponing this for later