BRIDGE-858 Update swagger definition

# Summary

This updates the swagger so the user can list their attempts to pay (ATP) for a specific RTP GET /payables/rtps/{rtpID}/atps

# Test Plan

* Check the server starts ok
* Check the /docs page shows the new paths
* Check we can still carry out the operations from that page
* Check the unit tests all run and pass



BRIDGE-800 Update swagger definition

# Summary

This updates the swagger and end-to-end tests for the existing `/rtps`
paths to move them under `/receivables/rtps` to leave room for future
development of `/payables/rtps` for the counterparty/payer side.

# Test Plan

* Check the server starts ok
* Check the /docs page shows the new paths
* Check we can still carry out the operations from that page
* Check the unit tests all run and pass