WIP - Using the endpoint address for determining the connection string instead of callback address

DO NOT MERGE - Creating the PR to trigger the acceptance tests! 
-- Relates to #59

**Things to do**
- [x] Add additional databases (NServiceBus1 and NServiceBus2) in the build server agent to facilitate acceptance tests
- [ ] Add acceptance tests for this feature
- [ ] Make sure all the other acceptance tests pass with this fix