As a REST API consumer
I want to be able to easily add PNR records without having to retrieve/update them
So that adding or replacing records becomes a trivial operation when using APIs

Given that there is already support to create and update PNRs
When adding support to append or replace PNR records for an existing zone
Then when append_pnr is called in PnrService, then get_pnr and update_pnr should be used to retrieve/store the changes
And if the record key already exists, the value should be replaced before the PNR Zone is persisted
And multiple records can be added or replaced in the same operation

Given that the REST API will need to be updated
When adding append PNR record support
Then provide a PATCH endpoint at /anttp-0/pnr/{name}
And use put_pnr() on pnr_controller.rs as an example
And update /src/lib.rs with the additional pnr/{name} route, using other routes as a guide
And the request body should be the same as the put_pnr() operation, using PnrZone

Given the postman collection has tests for PNR create/update
When adding append PNR record support
Then the postman collection should be updated
And newman should be used to validate

Implementation Notes

- Place any unit tests at the bottom of the same file as the associated production code
- Increment patch version of anttp package in Cargo.toml
- Create a copy of this issue description and save to /spec using the name of this issue as the filename (with lower underscore case, starting with the 5 char padded issue number, e.g. 00001_issue_title.txt)