docs: add headers set by proxy outpost

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

website/docs/outposts/proxy.md

@@ -0,0 +1,16 @@
+---
+title: Proxy Outpost
+---
+
+The proxy outpost sets the following headers:
+
+```
+X-Auth-Username: akadmin # The username of the currently logged in user
+X-Forwarded-Email: root@localhost # The email address of the currently logged in user
+X-Forwarded-Preferred-Username: akadmin  # The username of the currently logged in user
+X-Forwarded-User: 900347b8a29876b45ca6f75722635ecfedf0e931c6022e3a29a8aa13fb5516fb # The hashed identifier of the currently logged in user.
+```
+
+Additionally, you can set `additionalHeaders` on groups or users to set additional headers.
+
+If you enable *Set HTTP-Basic Authentication* option, the HTTP Authorization header is being set.

website/sidebars.js

@@ -34,6 +34,7 @@ module.exports = {
             label: "Outposts",
             items: [
                 "outposts/outposts",
+                "outposts/proxy",
                 "outposts/upgrading",
                 "outposts/manual-deploy-docker-compose",
                 "outposts/manual-deploy-kubernetes",