docs: remove empty index pages

It seems more confusing without actual content, which can be added on an
overview page.

Add the new instant load feature as well.

docs/concepts/index.md

@@ -1 +0,0 @@
-# Concepts

docs/getting-started/index.md

@@ -1 +0,0 @@
-# Getting started

docs/how-to-guides/index.md

@@ -1 +0,0 @@
-# How-to guides

docs/how-to-guides/troubleshooting/argocd.md

@@ -1,3 +0,0 @@
-# ArgoCD
-
-TODO (PR welcomed)

docs/how-to-guides/troubleshooting/cert-manager.md

@@ -1,3 +0,0 @@
-# cert-manager
-
-TODO (PR welcomed)

docs/how-to-guides/troubleshooting/gitea.md

@@ -1,3 +0,0 @@
-# Gitea
-
-TODO (PR welcomed)

docs/how-to-guides/troubleshooting/index.md

@@ -1 +0,0 @@
-# Troubleshooting

docs/installation/index.md

@@ -1 +0,0 @@
-# Installation

docs/installation/production/index.md

@@ -1 +0,0 @@
-# Production

docs/reference/architecture/index.md

@@ -1 +0,0 @@
-# Architecture

docs/reference/index.md

@@ -1 +0,0 @@
-# Reference

mkdocs.yml

@@ -11,7 +11,8 @@ theme:
   palette:
     primary: black
   features:
-    - navigation.indexes
+    - navigation.expand
+    - navigation.instant
     - navigation.sections
     - search.highlight
     - search.share
@@ -38,28 +39,23 @@ markdown_extensions:
 nav:
   - Home: index.md
   - Installation:
-    - installation/index.md
     - installation/sandbox.md
     - Production:
-      - installation/production/index.md
       - installation/production/prerequisites.md
       - installation/production/external-resources.md
       - installation/production/configuration.md
       - installation/production/deployment.md
     - installation/post-installation.md
   - Getting started:
-    - getting-started/index.md
     - getting-started/user-onboarding.md
     - getting-started/install-pre-commit-hooks.md
   - Concepts:
-    - concepts/index.md
     - concepts/pxe-boot.md
     - concepts/secrets-management.md
     - concepts/certificate-management.md
     - concepts/tools-container.md
     - concepts/testing.md
   - How-to guides:
-    - how-to-guides/index.md
     - how-to-guides/alternate-dns-setup.md
     - how-to-guides/expose-services-to-the-internet.md
     - how-to-guides/use-both-github-and-gitea.md
@@ -70,15 +66,9 @@ nav:
     - how-to-guides/media-management.md
     - how-to-guides/updating-documentation.md
     - Troubleshooting:
-      - how-to-guides/troubleshooting/index.md
-      - how-to-guides/troubleshooting/argocd.md
-      - how-to-guides/troubleshooting/cert-manager.md
-      - how-to-guides/troubleshooting/gitea.md
       - how-to-guides/troubleshooting/pxe-boot.md
   - Reference:
-    - reference/index.md
     - Architecture:
-      - reference/architecture/index.md
       - reference/architecture/overview.md
       - reference/architecture/networking.md
       - reference/architecture/decision-records.md