fix(api): introduce gitlab proxy package

api/http/proxy/factory/gitlab.go

@@ -0,0 +1,19 @@
+package factory
+
+import (
+	"net/http"
+	"net/url"
+
+	"github.com/portainer/portainer/api/http/proxy/factory/gitlab"
+)
+
+func newGitlabProxy(uri string) (http.Handler, error) {
+	url, err := url.Parse(uri)
+	if err != nil {
+		return nil, err
+	}
+
+	proxy := newSingleHostReverseProxyWithHostHeader(url)
+	proxy.Transport = gitlab.NewTransport()
+	return proxy, nil
+}