feat: add configuration to only push mirror selected branches (#7823)

Adds the ability to selectively choose which branches are pushed to a mirror.

This change adds an additional text box on the repository settings for each push mirror. Existing behavior is preserved when the field is left blank.

When the repository is being pushed, only branches matching the comma separated branch filter are pushed.

Resolves forgejo/forgejo#7242

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/7823
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Co-authored-by: Paul Campbell <pcampbell@kemitix.net>
Co-committed-by: Paul Campbell <pcampbell@kemitix.net>

services/forms/repo_form.go

@@ -141,6 +141,7 @@ type RepoSettingForm struct {
 	PushMirrorSyncOnCommit bool
 	PushMirrorInterval     string
 	PushMirrorUseSSH       bool
+	PushMirrorBranchFilter string `binding:"MaxSize(2048)" preprocess:"TrimSpace"`
 	Private                bool
 	Template               bool
 	EnablePrune            bool