[v24.1.x] [CORE-7152] Admin: Introduce GET /v1/features/enterprise endpoint

[vbotbuildovich]

Backport #23314 to branch v24.1.x. Note that this issue was created as a placeholder, since the original PR's commit(s) could not be automatically cherry-picked.
Here are the commands to execute:

git checkout v24.1.x
git checkout -b vbotbuildovich/backport-23314-v24.1.x-583
git cherry-pick -x bf972c04d8 067df42f1d 653d5a979a d6e33cd177 5fdc178250 b5c06fa59d ebfdd7fe27

git push origin vbotbuildovich/backport-23314-v24.1.x-583
gh pr create \
  --title "[v24.1.x] [CORE-7152] Admin: Introduce `GET /v1/features/enterprise` endpoint" \
  --base "v24.1.x" \
  --label "kind/backport" \
  --head "vbotbuildovich/backport-23314-v24.1.x-583" \
  --draft \
  --repo "redpanda-data/redpanda" \
  --milestone "v24.1.x-next" \
  --body "Backport of PR https://github.com/redpanda-data/redpanda/pull/23314 "

[CORE-7152]: https://redpandadata.atlassian.net/browse/CORE-7152?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

[oleiman]

closed by #23761