implement gitlab org catalog provider

Signed-off-by: Dominik Pfaffenbauer <dominik@pfaffenbauer.at>

docs/integrations/gitlab/org.md

@@ -0,0 +1,29 @@
+---
+id: org
+title: GitLab Org
+sidebar_label: Org Data
+description: Importing users and groups from a GitLab organization into Backstage
+---
+
+The Backstage catalog can be set up to ingest organizational data - users and
+teams - directly from an organization in GitLab. The result
+is a hierarchy of
+[`User`](../../features/software-catalog/descriptor-format.md#kind-user) and
+[`Group`](../../features/software-catalog/descriptor-format.md#kind-group) kind
+entities that mirror your org setup.
+
+```yaml
+integrations:
+  gitlab:
+    - host: gitlab.com
+      token: ${GITLAB_TOKEN}
+```
+
+```yaml
+catalog:
+  providers:
+    gitlab:
+      yourProviderId:
+        host: gitlab.com
+        orgEnabled: true
+```