API: enable proxying datasource calls using the datasource UID (#47634)

* Introduce additional routes

pkg/api/dataproxy.go

@@ -5,3 +5,7 @@ import "github.com/grafana/grafana/pkg/models"
 func (hs *HTTPServer) ProxyDataSourceRequest(c *models.ReqContext) {
 	hs.DataProxy.ProxyDataSourceRequest(c)
 }
+
+func (hs *HTTPServer) ProxyDataSourceRequestWithUID(c *models.ReqContext) {
+	hs.DataProxy.ProxyDatasourceRequestWithUID(c)
+}