Refactor "route" related code, fix Safari cookie bug (#24330)

Fix #24176

Clean some misuses of route package, clean some legacy FIXMEs

---------

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

routers/web/misc/misc.go

@@ -0,0 +1,49 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package misc
+
+import (
+	"net/http"
+	"os"
+	"path"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/httpcache"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+func SSHInfo(rw http.ResponseWriter, req *http.Request) {
+	if !git.SupportProcReceive {
+		rw.WriteHeader(http.StatusNotFound)
+		return
+	}
+	rw.Header().Set("content-type", "text/json;charset=UTF-8")
+	_, err := rw.Write([]byte(`{"type":"gitea","version":1}`))
+	if err != nil {
+		log.Error("fail to write result: err: %v", err)
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	rw.WriteHeader(http.StatusOK)
+}
+
+func DummyOK(w http.ResponseWriter, req *http.Request) {
+	w.WriteHeader(http.StatusOK)
+}
+
+func RobotsTxt(w http.ResponseWriter, req *http.Request) {
+	filePath := path.Join(setting.CustomPath, "robots.txt")
+	fi, err := os.Stat(filePath)
+	if err == nil && httpcache.HandleTimeCache(req, w, fi) {
+		return
+	}
+	http.ServeFile(w, req, filePath)
+}
+
+func StaticRedirect(target string) func(w http.ResponseWriter, req *http.Request) {
+	return func(w http.ResponseWriter, req *http.Request) {
+		http.Redirect(w, req, path.Join(setting.StaticURLPrefix, target), http.StatusMovedPermanently)
+	}
+}