feat: download transitive autodoc manifests

[paullatzelsperger]

What this PR changes/adds

This PR adds a gradle task downloadManifests, that downloads the -manifest.json from Maven for every org.eclipse.edc dependency.

Downstream projects, such as Tractus-X, that have dependencies onto EDC modules, can now merge their autodoc manifests with those coming from EDC.

Usually, the sequence is this:

./gradlew autodoc
./gradlew downloadManifests
./gradlew mergeManifests
./gradlew doc2md

which will produce a Markdown file containing documentation about the code base plus any transitive EDC dependencies.

Alternatively, they can be run together:

./gradlew autodoc downloadManifests mergeManifests doc2md --no-parallel

Why it does that

easily create documentation

Further notes

• these gradle tasks run async and potentially multithreaded, so they really should be called in separate gradle invocations or with the --no-parallel option

Linked Issue(s)

Closes # <-- insert Issue number if one exists

[wolf4ood]

🚀