Access repos by their ids (#1691)

closes #1295 
closes #648

# TODO
- [x] add new routes with `:repoID`
- [x] load repo in middleware using `:repoID` if present
- [x] update UI routes `:owner/:name` to `:repoID`
- [x] load repos using id in UI
- [x] add lookup endpoint `:owner/:name` to `:repoID`
- [x] redirect `:owner/:name` to `:repoID` in UI
- [x] use badge with `:repoID` route in UI
- [x] update `woodpecker-go`
- [x] check cli
- [x] add migrations / deprecation notes
- [x] check if #648 got solved directly
- [x] Test
  - [x] create repo
  - [x] repo pages
  - [x] ui redirects
  - [x] forge status links

server/forge/gitlab/gitlab.go

@@ -290,12 +290,6 @@ func (g *GitLab) Repos(ctx context.Context, user *model.User) ([]*model.Repo, er
 				return nil, err
 			}
 
-			// TODO(648) remove when woodpecker understands nested repos
-			if strings.Count(repo.FullName, "/") > 1 {
-				log.Debug().Msgf("Skipping nested repository %s for user %s, because they are not supported, yet (see #648).", repo.FullName, user.Login)
-				continue
-			}
-
 			repos = append(repos, repo)
 		}