Add package registry cleanup rules (#21658)

Fixes #20514
Fixes #20766
Fixes #20631

This PR adds Cleanup Rules for the package registry. This allows to
delete unneeded packages automatically. Cleanup rules can be set up from
the user or org settings.
Please have a look at the documentation because I'm not a native english
speaker.

Rule Form

![grafik](https://user-images.githubusercontent.com/1666336/199330792-c13918a6-e196-4e71-9f53-18554515edca.png)

Rule List

![grafik](https://user-images.githubusercontent.com/1666336/199331261-5f6878e8-a80c-4985-800d-ebb3524b1a8d.png)

Rule Preview

![grafik](https://user-images.githubusercontent.com/1666336/199330917-c95e4017-cf64-4142-a3e4-af18c4f127c3.png)

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

services/forms/package_form.go

@@ -0,0 +1,31 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package forms
+
+import (
+	"net/http"
+
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/web/middleware"
+
+	"gitea.com/go-chi/binding"
+)
+
+type PackageCleanupRuleForm struct {
+	ID            int64
+	Enabled       bool
+	Type          string `binding:"Required;In(composer,conan,container,generic,helm,maven,npm,nuget,pub,pypi,rubygems,vagrant)"`
+	KeepCount     int    `binding:"In(0,1,5,10,25,50,100)"`
+	KeepPattern   string `binding:"RegexPattern"`
+	RemoveDays    int    `binding:"In(0,7,14,30,60,90,180)"`
+	RemovePattern string `binding:"RegexPattern"`
+	MatchFullName bool
+	Action        string `binding:"Required;In(save,remove)"`
+}
+
+func (f *PackageCleanupRuleForm) Validate(req *http.Request, errs binding.Errors) binding.Errors {
+	ctx := context.GetContext(req)
+	return middleware.Validate(errs, ctx.Data, f, ctx.Locale)
+}