API: Move AllowedReactions endpoint into GetGenneralUI endpoint + creat new swagger section settings (#11854)

* move Setting function into its own package

* swagger add&use new section "settings"

* move api AllowedReactions into general UI-Settings endpoint

* prepare TEST

* lint

routers/api/v1/swagger/misc.go

@@ -21,10 +21,3 @@ type swaggerResponseStringSlice struct {
 	// in:body
 	Body []string `json:"body"`
 }
-
-// GeneralRepoSettings
-// swagger:response GeneralRepoSettings
-type swaggerResponseGeneralRepoSettings struct {
-	// in:body
-	Body api.GeneralRepoSettings `json:"body"`
-}