Read encrypted_recovery_code_digest column

[jmhooper]

Why: So that we can continue the migration to recovery code digests
that mirror password digests

• For DB changes, check for missing indexes, check to see if the changes
  affect other apps (such as the dashboard), make sure the DB columns in the
  various environments are properly populated, coordinate with devops, plan
  migrations in separate steps.

• For route changes, make sure GET requests don't change state or result in
  destructive behavior. GET requests should only result in information being
  read, not written.

• For encryption changes, make sure it is compatible with data that was
  encrypted with the old code.

• For secrets changes, make sure to update the S3 secrets bucket with the
  new configs in all environments.

• Do not disable Rubocop or Reek offenses unless you are absolutely sure
  they are false positives. If you're not sure how to fix the offense, please
  ask a teammate.

• When reading data, write tests for nil values, empty strings,
  and invalid formats.

• When calling redirect_to in a controller, use _url, not _path.

• When adding user data to the session, use the user_session helper
  instead of the session helper so the data does not persist beyond the user's
  session.

• When adding a new controller that requires the user to be fully
  authenticated, make sure to add before_action :confirm_two_factor_authenticated.

[jmhooper]

We should not merge this until #2220 is deployed

[jmhooper]

Ignoring this here. This method will be deleted in the PR that stops reading from these columns

[jmhooper]

Also, the base for this PR is jmhooper-verify-password for the purpose of showing the relevant changes. Once that branch is merged, this will need to be rebased and have its base changed to master.

[jmhooper]

This has been rebased and I've changed the base. We'll still want to wait until after the next release before we merge.

[jmhooper]

Okay, #2220 has been deployed and the recovery code digests have been backfilled. This one should be ready to go once it is reviewed.

[jgsmith-usds]

LGTM