Add Arch package registry (#32692)

Close #25037
Close #31037

This PR adds a Arch package registry usable with pacman.

![grafik](https://github.com/user-attachments/assets/81cdb0c2-02f9-4733-bee2-e48af6b45224)

Rewrite of #25396 and #31037. You can follow [this
tutorial](https://wiki.archlinux.org/title/Creating_packages) to build a
package for testing.

Docs PR: https://gitea.com/gitea/docs/pulls/111

Co-authored-by: [d1nch8g@ion.lc](mailto:d1nch8g@ion.lc)
Co-authored-by: @ExplodingDragon

---------

Co-authored-by: dancheg97 <dancheg97@fmnx.su>
Co-authored-by: dragon <ExplodingFKL@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/packages/arch/search.go

@@ -0,0 +1,38 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package arch
+
+import (
+	"context"
+
+	packages_model "code.gitea.io/gitea/models/packages"
+	arch_module "code.gitea.io/gitea/modules/packages/arch"
+)
+
+// GetRepositories gets all available repositories
+func GetRepositories(ctx context.Context, ownerID int64) ([]string, error) {
+	return packages_model.GetDistinctPropertyValues(
+		ctx,
+		packages_model.TypeArch,
+		ownerID,
+		packages_model.PropertyTypeFile,
+		arch_module.PropertyRepository,
+		nil,
+	)
+}
+
+// GetArchitectures gets all available architectures for the given repository
+func GetArchitectures(ctx context.Context, ownerID int64, repository string) ([]string, error) {
+	return packages_model.GetDistinctPropertyValues(
+		ctx,
+		packages_model.TypeArch,
+		ownerID,
+		packages_model.PropertyTypeFile,
+		arch_module.PropertyArchitecture,
+		&packages_model.DistinctPropertyDependency{
+			Name:  arch_module.PropertyRepository,
+			Value: repository,
+		},
+	)
+}