feat: make action runs available in api (#7699)

## Summary

Inspired by https://docs.github.com/en/rest/actions/workflow-runs?apiVersion=2022-11-28#list-workflow-runs-for-a-repository and https://docs.github.com/en/rest/actions/workflow-runs?apiVersion=2022-11-28#get-a-workflow-run

## Checklist

The [contributor guide](https://forgejo.org/docs/next/contributor/) contains information that will be helpful to first time contributors. There also are a few [conditions for merging Pull Requests in Forgejo repositories](https://codeberg.org/forgejo/governance/src/branch/main/PullRequestsAgreement.md). You are also welcome to join the [Forgejo development chatroom](https://matrix.to/#/#forgejo-development:matrix.org).

### Tests

- I added test coverage for Go changes...
  - [ ] in their respective `*_test.go` for unit tests.
  - [x] in the `tests/integration` directory if it involves interactions with a live Forgejo server.
- I added test coverage for JavaScript changes...
  - [ ] in `web_src/js/*.test.js` if it can be unit tested.
  - [ ] in `tests/e2e/*.test.e2e.js` if it requires interactions with a live Forgejo server (see also the [developer guide for JavaScript testing](https://codeberg.org/forgejo/forgejo/src/branch/forgejo/tests/e2e/README.md#end-to-end-tests)).

### Documentation

- [ ] I created a pull request [to the documentation](https://codeberg.org/forgejo/docs) to explain to Forgejo users how to use this change.
- [x] I did not document these changes and I do not expect someone else to do it.

### Release notes

- [ ] I do not want this change to show in the release notes.
- [x] I want the title to show in the release notes with a link to this pull request.
- [ ] I want the content of the `release-notes/<pull request number>.md` to be be used for the release notes instead of the title.

<!--start release-notes-assistant-->

## Release notes
<!--URL:https://codeberg.org/forgejo/forgejo-->
- Features
  - [PR](https://codeberg.org/forgejo/forgejo/pulls/7699): <!--number 7699 --><!--line 0 --><!--description bWFrZSBhY3Rpb24gcnVucyBhdmFpbGFibGUgaW4gYXBp-->make action runs available in api<!--description-->
<!--end release-notes-assistant-->

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7699
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>
Co-authored-by: klausfyhn <klausfyhn@gmail.com>
Co-committed-by: klausfyhn <klausfyhn@gmail.com>

routers/api/v1/api.go

@@ -1172,6 +1172,10 @@ func Routes() *web.Route {
 				}, reqToken(), reqAdmin())
 				m.Group("/actions", func() {
 					m.Get("/tasks", repo.ListActionTasks)
+					m.Group("/runs", func() {
+						m.Get("", repo.ListActionRuns)
+						m.Get("/{run_id}", repo.GetActionRun)
+					})
 
 					m.Group("/workflows", func() {
 						m.Group("/{workflowname}", func() {