Working on the docs.elgg.org migration

DON'T merge yet, as I'm working on more pages.

I wanted to know if this is the way to go for #6812 

contains the following docs pages

- [How I customised Elgg](http://docs.elgg.org/wiki/How_I_customised_Elgg) (as a link the the Elgg showcase page)
- [Budokin.com](http://docs.elgg.org/wiki/Budokin.com) (as a link the the Elgg showcase page)
- [Plugin skeleton](http://docs.elgg.org/wiki/Plugin_skeleton)
- [Plugins/Dashboard](http://docs.elgg.org/wiki/Plugins/Dashboard)
- [Plugins/File repository](http://docs.elgg.org/wiki/Plugins/File_repository)
- [Plugins/Groups](http://docs.elgg.org/wiki/Plugins/Groups)
- [Plugins/Profile](http://docs.elgg.org/wiki/Plugins/Profile)
- [Plugins/Pages](http://docs.elgg.org/wiki/Plugins/Pages)
- [Plugins/Messageboard](http://docs.elgg.org/wiki/Plugins/Messageboard)
- [Plugins/Messages](http://docs.elgg.org/wiki/Plugins/Messages)
- [Plugins/Blog](http://docs.elgg.org/wiki/Plugins/Blog)
- [Plugins/TheWire](http://docs.elgg.org/wiki/Plugins/TheWire)
- [Engine/Controllers/PageHandler](http://docs.elgg.org/wiki/Engine/Controllers/PageHandler)
- [Helpers](http://docs.elgg.org/wiki/Helpers)
- [What is context and how does it work?](http://docs.elgg.org/wiki/What_is_context_and_how_does_it_work%3F)
- [Pluginsettings](http://docs.elgg.org/wiki/Pluginsettings)
- [Permissions Check](http://docs.elgg.org/wiki/Permissions_Check)
- [Engine/Authentication](http://docs.elgg.org/wiki/Engine/Authentication)