Developer 675 Fuse Connectors Page

Here's a first look at the Fuse connectors page.

Implemented:

* Pushes to the DCP based on the contents of the spreadsheet.
* Page generated by JS rather than statically at site build time. Makes it possible to implement filtering later.

Outstanding:

* Overview text needs providing
* Images need adding to static.jboss.org by the design team. This is contrary to the suggestion in the spreadsheet that they are configurable
* Default connector image needed
* Decision to display the connectors page is hard-coded. Better to decide based on presence of connectors.adoc. 
* The connectors.js could be simplified, however, I tried to keep the structure similar to projects.js. This was for two reasons. Firstly, because it will make it easier to add filters and featured connectors later and secondly, because we may want to refactor projects.js and connectors.js due to their similarity.
* Only ~115 connectors are being indexed. There should be ~150.
* Long descriptions need providing in the connectors spreadsheet. Currently the short description is used if the long description is missing.
* Connector code snippets need adding to the spreadsheet.
* More-details link missing

It's not very rubyish to use camel case in variable names. Instead use underscores. Also you can just do 
````
Parallel.each(site.fuse_connectors, in_threads: 40) do |(id, data)|
````
to avoid using lots of extra code to get the vars.