Refactor web package and context package (#25298)

1. The "web" package shouldn't depends on "modules/context" package,
instead, let each "web context" register themselves to the "web"
package.
2. The old Init/Free doesn't make sense, so simplify it
* The ctx in "Init(ctx)" is never used, and shouldn't be used that way
* The "Free" is never called and shouldn't be called because the SSPI
instance is shared

---------

Co-authored-by: Giteabot <teabot@gitea.io>

cmd/web.go

@@ -191,7 +191,7 @@ func runWeb(ctx *cli.Context) error {
 	}
 
 	// Set up Chi routes
-	c := routers.NormalRoutes(graceful.GetManager().HammerContext())
+	c := routers.NormalRoutes()
 	err := listen(c, true)
 	<-graceful.GetManager().Done()
 	log.Info("PID: %d Gitea Web Finished", os.Getpid())