add marketplace barebones to docs

Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Co-authored-by: Engelbracht, Keno <a22549483@noreply.gitea.eco.tsi-dev.otc-service.com>
Co-committed-by: Engelbracht, Keno <a22549483@noreply.gitea.eco.tsi-dev.otc-service.com>

otc_metadata/data/services/mkp.yaml

@@ -0,0 +1,16 @@
+---
+environment: internal
+repositories:
+- environment: internal
+  repo: docs/marketplace
+  type: gitea
+- environment: public
+  repo: opentelekomcloud-docs/marketplace
+  type: github
+service_category: other
+service_title: Marketplace
+service_type: mkp
+service_uri: marketplace
+teams:
+- name: docs-3rd-party-integration-rw
+  permission: write