feat: add Edrs controller

[ndr-brt]

Description

Implement Edrs management endpoint

notes

• this was tested using prism, that loads a mock server based on the official EDC management API spec as we did on the java client. This will make the tests faster, an issue to translate the other tests to the same method will come, then we could keep just a single end-to-end test.
• the yaml file used was downloaded from the EDC docs, an issue to download it automatically will come (to handle EDC version updates).

Closes #210

[fdionisi]

Looking great, @ndr-brt! There's really nothing that catches my eyes, but I'm also not super acquainted with the EDR endpoints.

Nice work!

[fdionisi]

Does it mean we'll be moving away from e2e tests against the connector?

[fdionisi]

Oh! I see #216 is related to that. I'm a bit hesitant in saying let's go 100% with it; somehow it would be nice to have a e2e test which can ensure everything is wired up correctly, but I admit this is also coming form a place of ignorance. So I would fully trust your direction.

[ndr-brt]

Sure, in the issue is reported that at least one E2E test should be kept, because otherwise we'll lose coverage, but currently we're testing the same things multiple times because we got a lot of e2e tests that are slow to run (on every new version the connector needs to be built again).
With the new structure every controller test suite will test only its own methods against prism to verify the structure, then few e2e will fill up the uncovered spots