docs(api): get openapi files from dependencies repository

[ndr-brt]

WHAT

Add a gradle task that downloads all the openapi specs of the dependencies and use them to build the merged spec to be uploaded to swaggerhub

WHY

documentation

FURTHER NOTES

• this will need to be refined further because currently downloads ALL the openapi spec, also the ones that likely we don't want to show in the docs (e.g. dsp, control...). at the moment there's no way to discriminate.

Part of #1393

[paullatzelsperger]

this should probably be in the root build file, because the dataplane also has an API and thus openAPI files

[ndr-brt]

I was thinking, do we need to list the dataplane api as well? Because those should be considered internal ones, same as "control" and "dsp", that's why I'm working to filter them out (update to PR will come up soon).
likely to external viewers only "management" and "observability" would be interesting, wdyt?

otherwise a possibility could be to publish them separately as we're doing on upstream

[paullatzelsperger]

well... I would not necessarily consider the dataplane signaling API external. And then there is the token-refresh API in Tractus-X, that is not part of the DPS, but I would still consider public. Thinking of third-party dataplanes, etc.
We can obviously do this in another iteration, but dataplane APIs should still be documented I think.

[ndr-brt]

not "external", but "internal".
token refresh is already part of the merged spec because it's not downloaded from maven repo but generated by the resolve task.

anyway I will add the task for both control-plane and data-plane, for management-api, observability-api and public-api, then let's wait for some feedback

[paullatzelsperger]

sorry, i meant to say that I would not consider them internal ofc.

token refresh is already part of the merged spec because it's not downloaded from maven repo but generated by the resolve task.

i know, my point was that the dataplane very much has APIs that are public, such as DPS and token refresh. especially with DPS i see no reason not to include it.