Add Debian package registry (#24426)

Co-authored-by: @awkwardbunny

This PR adds a Debian package registry.
You can follow [this
tutorial](https://www.baeldung.com/linux/create-debian-package) to build
a *.deb package for testing.
Source packages are not supported at the moment and I did not find
documentation of the architecture "all" and how these packages should be
treated.


![grafik](https://user-images.githubusercontent.com/1666336/218126879-eb80a866-775c-4c8e-8529-5797203a64e6.png)

Part of #20751.

Revised copy of #22854.

---------

Co-authored-by: Brian Hong <brian@hongs.me>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Giteabot <teabot@gitea.io>

models/user/setting.go

@@ -11,6 +11,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/modules/cache"
 	setting_module "code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 
 	"xorm.io/builder"
 )
@@ -42,6 +43,10 @@ func (err ErrUserSettingIsNotExist) Error() string {
 	return fmt.Sprintf("Setting[%s] is not exist", err.Key)
 }
 
+func (err ErrUserSettingIsNotExist) Unwrap() error {
+	return util.ErrNotExist
+}
+
 // IsErrUserSettingIsNotExist return true if err is ErrSettingIsNotExist
 func IsErrUserSettingIsNotExist(err error) bool {
 	_, ok := err.(ErrUserSettingIsNotExist)