Remove REST endpoints, fields that were deprecated in v4.x

[nscuro]

Current Behavior

There are multiple REST endpoints, and fields of model classes that were deprecated in v4.x (i.e. via @Deprecated annotation).

• https://github.com/search?q=repo%3ADependencyTrack%2Fhyades-apiserver+%22%40Deprecated%22&type=code
• https://github.com/search?q=repo%3ADependencyTrack%2Fhyades+%22%40Deprecated%22&type=code

Note

Work on this issue either needs to be delayed until shortly before GA, or we need to keep it open until then, and continuously work on it. It's possible that new v4.x releases will introduce more deprecations.

Proposed Behavior

Since Hyades marks a new major release, we should remove deprecated code prior to release.

Make sure to note removals in the docs: https://github.com/DependencyTrack/hyades/blob/main/docs/getting-started/changes-over-v4.md

Checklist

• I have read and understand the contributing guidelines
• I have checked the existing issues for whether this enhancement was already requested