Implement recent commits graph (#29210)

This is the implementation of Recent Commits page. This feature was
mentioned on #18262.

It adds another tab to Activity page called Recent Commits. Recent
Commits tab shows number of commits since last year for the repository.

routers/web/web.go

@@ -1402,6 +1402,10 @@ func registerRoutes(m *web.Route) {
 				m.Get("", repo.CodeFrequency)
 				m.Get("/data", repo.CodeFrequencyData)
 			})
+			m.Group("/recent-commits", func() {
+				m.Get("", repo.RecentCommits)
+				m.Get("/data", repo.RecentCommitsData)
+			})
 		}, context.RepoRef(), repo.MustBeNotEmpty, context.RequireRepoReaderOr(unit.TypePullRequests, unit.TypeIssues, unit.TypeReleases))
 
 		m.Group("/activity_author_data", func() {