Extract developer site (#5249)

* Extract developer site

* Fix title in sidebar

* Update dev section reference

* Update edit in github link on help page

source/developers/helpers.markdown

@@ -9,18 +9,6 @@ sharing: true
 footer: true
 ---
 
-There are a bunch of online services which can help you if you are developing for Home Assistant or maintaining components. Some of these are directly connected to Pull Requests and the repositories, while others publish details and updates on our [Discord chat server][discord-devs].
-
-- [Coveralls][coveralls]
-- [Travis CI][travis-ci]
-- [gemnasium][gemnasium]
-- [Requires.io][requires-io]
-- [Pivotal Tracker][pivotal]
-
-[coveralls]: https://coveralls.io/github/home-assistant/home-assistant
-[travis-ci]: https://travis-ci.org/home-assistant/home-assistant
-[gemnasium]: https://gemnasium.com/github.com/home-assistant/home-assistant
-[requires-io]: https://requires.io/github/home-assistant/home-assistant/requirements/?branch=dev
-[pivotal]: https://www.pivotaltracker.com/n/projects/1250084
-
-[discord-devs]: https://discord.gg/8X8DTH4
+<script>
+window.location = 'https://developers.home-assistant.io/en';
+</script>