website/docs: move configuration to its own document

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

website/docs/installation/configuration.md

@@ -1,8 +1,8 @@
 ---
-title: docker-compose configuration
+title: Configuration
 ---
 
-These are all the configuration options you can set via docker-compose. These don't apply to Kubernetes, as those settings are configured via helm.
+These are all the configuration options you can set via environment variables.
 
 Append any of the following keys to your `.env` file, and run `docker-compose up -d` to apply them.
 

website/sidebars.js

@@ -14,7 +14,7 @@ module.exports = {
             items: [
                 "installation/index",
                 "installation/docker-compose",
-                "installation/docker-compose-config",
+                "installation/configuration",
                 "installation/reverse-proxy",
                 "installation/kubernetes",
                 "installation/beta",