Add validation features for ACP workflow

[stl-steve-moore]

When testing the ACP workflow, we want the Toolkit to send a Patient Discovery request with SAML assertions that include an identifier for the test patient. The system under test sends a query for and then retrieves a consent document from the Toolkit simulator. Only after reviewing the consent document does the system understand complete the Patient Discovery response. We need these additions in validation:

1. Extend the work that search the simulators for transactions that meet criteria. Add a case for a transaction (say Cross Domain Document Query) that takes place after the initial Patient Discovery request goes out.
2. Should probably extend this to make sure the transaction also happens before the Patient Discovery response is made
3. Add a validator that will call the Gazelle External Validation Service to test the structure/coding of the Patient Discovery response.