feat(plugins): major improvement in plugins golang code

pkg/plugins/datasource_plugin.go

@@ -0,0 +1,25 @@
+package plugins
+
+import "encoding/json"
+
+type DataSourcePlugin struct {
+	FrontendPluginBase
+	DefaultMatchFormat string `json:"defaultMatchFormat"`
+	Annotations        bool   `json:"annotations"`
+	Metrics            bool   `json:"metrics"`
+	BuiltIn            bool   `json:"builtIn"`
+	Mixed              bool   `json:"mixed"`
+	App                string `json:"app"`
+}
+
+func (p *DataSourcePlugin) Load(decoder *json.Decoder, pluginDir string) error {
+	if err := decoder.Decode(&p); err != nil {
+		return err
+	}
+
+	p.PluginDir = pluginDir
+	p.initFrontendPlugin()
+	DataSources[p.Id] = p
+
+	return nil
+}