doc: add a section howto

This section contains advanced configuration howtos.

docs/add-radicale.rst

@@ -1,5 +1,5 @@
-How to Add Radicale to SNM
-==========================
+Add Radicale
+============
 
 Configuration by @dotlambda
 

docs/backup-guide.rst

@@ -1,9 +1,9 @@
-A Complete Backup Guide
-=======================
+Backup Guide
+============
 
-This is really easy. First off you should have a backup of your
-``configuration.nix`` file where you have the server config (but that is
-already in a git repository right?)
+First off you should have a backup of your ``configuration.nix`` file
+where you have the server config (but that is already in a git
+repository right?)
 
 Next you need to backup ``/var/vmail`` or whatever you have specified
 for the option ``mailDirectory``. This is where all the mails reside.

docs/howto-develop.rst

@@ -1,5 +1,5 @@
-How to Develop SNM
-==================
+Contribute or troubleshoot
+==========================
 
 Run NixOS tests
 ---------------

docs/index.rst

@@ -16,11 +16,17 @@ Welcome to NixOS Mailserver's documentation!
    quick-start
    setup-guide
    howto-develop
-   backup-guide
-   howto-add-radicale
-   rspamd-tuning
    release-notes
 
+.. toctree::
+   :maxdepth: 1
+   :caption: How-to
+
+   backup-guide
+   add-radicale
+   rspamd-tuning
+
+
 Indices and tables
 ==================
 

docs/rspamd-tuning.rst

@@ -1,5 +1,5 @@
-How to tune spam filtering
-==========================
+Tune spam filtering
+===================
 
 SNM comes with the `rspamd spam filtering system <https://rspamd.com/>`_
 enabled by default. Although its out-of-the-box performance is good, you

docs/setup-guide.rst

@@ -1,5 +1,5 @@
-A Complete Setup Guide
-======================
+Setup Guide
+===========
 
 Mail servers can be a tricky thing to set up. This guide is supposed to
 run you through the most important steps to achieve a 10/10 score on