Add initial Kubernetes config files

This includes all the resources currently running on https://gitea.kosmos.org

It sets up a persistent data volume for the MySQL database, one for the
Gitea data, that Gitea calls the custom folder (config, attachment,
avatars, logs, etc). We mount that persistent data volume as
/data/gitea. It also creates a Let's Encrypt certificate for
gitea.kosmos.org, also saved to the custom folder.

This also includes two scripts:

* `./script/get_secrets` downloads the secrets to the local filesystem so
they can be edited
* `./script/replace_secrets` deletes the remote secrets and creates them
again from the local ones in kubernetes/config/*

Closes #6

script/get_secrets

@@ -0,0 +1,15 @@
+#!/usr/bin/env ruby
+
+require 'yaml'
+require 'base64'
+
+secret = `kubectl get secret gitea-config -o yaml`
+yaml = YAML.load(secret)
+
+yaml['data'].each do |key, data|
+  filename = File.join('kubernetes', 'config', key)
+  File.open(filename, "w+") do |f|
+    puts "Writing #{filename}"
+    f.write Base64.decode64(data)
+  end
+end