website/docs: re-organise core concepts

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

website/docs/core/applications.md

@@ -1,5 +1,6 @@
 ---
 title: Applications
+slug: /applications
 ---
 
 Applications in authentik are the counterpart of providers. They exist in a 1-to-1 relationship, each application needs a provider and every provider can be used with one application.

website/docs/core/tenants.md

@@ -1,5 +1,6 @@
 ---
 title: Tenants
+slug: /tenants
 ---
 
 authentik support soft multi-tenancy. This means that you can configure several options depending on domain, but all the objects like applications, providers, etc, are still global. This can be handy to use the same authentik instance, but branded differently for different domains.

website/docs/core/terminology.md

@@ -1,6 +1,7 @@
 ---
 id: terminology
 title: Terminology
+slug: /terminology
 ---
 
 ![](/img/authentik_objects.svg)

website/sidebars.js

@@ -4,10 +4,6 @@ module.exports = {
             type: "doc",
             id: "index",
         },
-        {
-            type: "doc",
-            id: "terminology",
-        },
         {
             type: "category",
             label: "Installation",
@@ -23,8 +19,10 @@ module.exports = {
             ],
         },
         {
-            type: "doc",
+            type: "category",
-            id: "applications",
+            label: "Core Concepts",
+            collapsed: false,
+            items: ["core/terminology", "core/applications", "core/tenants"],
         },
         {
             type: "category",
@@ -121,10 +119,6 @@ module.exports = {
             label: "Users & Groups",
             items: ["user-group/user", "user-group/group"],
         },
-        {
-            type: "doc",
-            id: "tenants",
-        },
         {
             type: "category",
             label: "Maintenance",