Dashboards: Add a config setting that limits the number of series that will be displayed in a panel. Users can opt in to render all series. (#103405)

* Limit series in panels in dashboards

* fix mangled comment

pkg/setting/setting.go

@@ -226,6 +226,7 @@ type Cfg struct {
 	MinRefreshInterval          string
 	DefaultHomeDashboardPath    string
 	DashboardPerformanceMetrics []string
+	PanelSeriesLimit            int
 
 	// Auth
 	LoginCookieName               string
@@ -1149,6 +1150,7 @@ func (cfg *Cfg) parseINIFile(iniFile *ini.File) error {
 	cfg.MinRefreshInterval = valueAsString(dashboards, "min_refresh_interval", "5s")
 	cfg.DefaultHomeDashboardPath = dashboards.Key("default_home_dashboard_path").MustString("")
 	cfg.DashboardPerformanceMetrics = util.SplitString(dashboards.Key("dashboard_performance_metrics").MustString(""))
+	cfg.PanelSeriesLimit = dashboards.Key("panel_series_limit").MustInt(0)
 
 	if err := readUserSettings(iniFile, cfg); err != nil {
 		return err