feat(cli): add default plugin folder for MAC OS

closes #5806

pkg/cmd/grafana-cli/utils/grafana_path.go

@@ -0,0 +1,46 @@
+package utils
+
+import (
+	"os"
+
+	"github.com/grafana/grafana/pkg/cmd/grafana-cli/logger"
+)
+
+func GetGrafanaPluginDir(currentOS string) string {
+	//currentOS := runtime.GOOS
+
+	if currentOS == "windows" {
+		return returnOsDefault(currentOS)
+	}
+
+	pwd, err := os.Getwd()
+
+	if err != nil {
+		logger.Error("Could not get current path. using default")
+		return returnOsDefault(currentOS)
+	}
+
+	if isDevenvironment(pwd) {
+		return "../data/plugins"
+	}
+
+	return returnOsDefault(currentOS)
+}
+
+func isDevenvironment(pwd string) bool {
+	// if ../conf/defaults.ini exists, grafana is not installed as package
+	// that its in development environment.
+	_, err := os.Stat("../conf/defaults.ini")
+	return err == nil
+}
+
+func returnOsDefault(currentOs string) string {
+	switch currentOs {
+	case "windows":
+		return "../data/plugins"
+	case "darwin":
+		return "/usr/local/var/lib/grafana/plugins"
+	default: //"linux"
+		return "/var/lib/grafana/plugins"
+	}
+}