Improve API URL documentation

[Pfeil]

Describe the bug

The openApi/swagger documentation displays some URLs in a misinterpretable way and does not provide a proper testing interface.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://kit-data-manager.github.io/webpage/typed-pid-maker/openapi.html
2. Check the following urls and their swagger interaction possibilities

• for resolving pids (GET /api/v1/pit/pid/**)
• for retriving known PIDs (GET /api/v1/pit/known-pid/**)
• for updating PIDs (GET /api/v1/pit/pid/**)

Expected behavior

• when trying out the call in the swagger interface, there should be an input element for assigning a value to the ** placeholder
• it would be nicer to have a variable name instead of **

Additional context

• It is an issue that PIDs may contain slashes
• One approach would be for the API to assume a "prefix/suffix" scheme, but it may limit the API to the common Handle-PID scheme. On the other hand, we internally have a suffix generator and some prefix/suffix semantic anyway...
• We could instead investigate if we can catch all fragments in a list in another way and join them, and how this is being displayed in the swagger interface.