Chore: Hugo upgrade (#17494)

* Fix: Upgrade hugo wip

* Chore: Rename index to _index for latest hugo

* Chore: Use relative refs, no starting slash

* Feat: Add possibility to mount layouts from grafana.org project

docs/sources/http_api/_index.md

@@ -0,0 +1,38 @@
++++
+title = "HTTP API"
+description = "Grafana HTTP API"
+keywords = ["grafana", "http", "documentation", "api", "overview"]
+type = "docs"
+[menu.docs]
+name = "HTTP API"
+identifier = "http_api"
+weight = 9
++++
+
+
+# HTTP API Reference
+
+The Grafana backend exposes an HTTP API, the same API is used by the frontend to do everything from saving
+dashboards, creating users and updating data sources.
+
+## Supported HTTP APIs:
+
+
+* [Authentication API]({{< relref "http_api/auth.md" >}})
+* [Dashboard API]({{< relref "http_api/dashboard.md" >}})
+* [Dashboard Versions API]({{< relref "http_api/dashboard_versions.md" >}})
+* [Dashboard Permissions API]({{< relref "http_api/dashboard_permissions.md" >}})
+* [Folder API]({{< relref "http_api/folder.md" >}})
+* [Folder Permissions API]({{< relref "http_api/folder_permissions.md" >}})
+* [Folder/dashboard search API]({{< relref "http_api/folder_dashboard_search.md" >}})
+* [Data Source API]({{< relref "http_api/data_source.md" >}})
+* [Organization API]({{< relref "http_api/org.md" >}})
+* [Snapshot API]({{< relref "http_api/snapshot.md" >}})
+* [Annotations API]({{< relref "http_api/annotations.md" >}})
+* [Alerting API]({{< relref "http_api/alerting.md" >}})
+* [Alert Notification Channels API]({{< relref "http_api/alerting_notification_channels.md" >}})
+* [User API]({{< relref "http_api/user.md" >}})
+* [Team API]({{< relref "http_api/team.md" >}})
+* [Admin API]({{< relref "http_api/admin.md" >}})
+* [Preferences API]({{< relref "http_api/preferences.md" >}})
+* [Other API]({{< relref "http_api/other.md" >}})