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>

modules/setting/packages.go

@@ -22,6 +22,7 @@ var (
 		LimitTotalOwnerCount int64
 		LimitTotalOwnerSize  int64
 		LimitSizeAlpine      int64
+		LimitSizeArch        int64
 		LimitSizeCargo       int64
 		LimitSizeChef        int64
 		LimitSizeComposer    int64
@@ -79,6 +80,7 @@ func loadPackagesFrom(rootCfg ConfigProvider) (err error) {
 
 	Packages.LimitTotalOwnerSize = mustBytes(sec, "LIMIT_TOTAL_OWNER_SIZE")
 	Packages.LimitSizeAlpine = mustBytes(sec, "LIMIT_SIZE_ALPINE")
+	Packages.LimitSizeArch = mustBytes(sec, "LIMIT_SIZE_ARCH")
 	Packages.LimitSizeCargo = mustBytes(sec, "LIMIT_SIZE_CARGO")
 	Packages.LimitSizeChef = mustBytes(sec, "LIMIT_SIZE_CHEF")
 	Packages.LimitSizeComposer = mustBytes(sec, "LIMIT_SIZE_COMPOSER")