Remove ONLY_SHOW_RELEVANT_REPOS setting (#21962)

Every user can already disable the filter manually, so the explicit
setting is absolutely useless and only complicates the logic.

Previously, there was also unexpected behavior when multiple query
parameters were present.

---------

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/setting/setting.go

@@ -241,7 +241,6 @@ var (
 		CustomEmojisMap       map[string]string `ini:"-"`
 		SearchRepoDescription bool
 		UseServiceWorker      bool
-		OnlyShowRelevantRepos bool
 
 		Notification struct {
 			MinTimeout            time.Duration
@@ -1123,7 +1122,6 @@ func loadFromConf(allowEmpty bool, extraConfig string) {
 	UI.DefaultShowFullName = Cfg.Section("ui").Key("DEFAULT_SHOW_FULL_NAME").MustBool(false)
 	UI.SearchRepoDescription = Cfg.Section("ui").Key("SEARCH_REPO_DESCRIPTION").MustBool(true)
 	UI.UseServiceWorker = Cfg.Section("ui").Key("USE_SERVICE_WORKER").MustBool(false)
-	UI.OnlyShowRelevantRepos = Cfg.Section("ui").Key("ONLY_SHOW_RELEVANT_REPOS").MustBool(false)
 
 	HasRobotsTxt, err = util.IsFile(path.Join(CustomPath, "robots.txt"))
 	if err != nil {