fixes #6519 - updating associations UI

Added associations to the UI:
+ subscriptions to content hosts and activation keys
+ activation keys to content hosts

I'm surprised htmlhint allowed this.  Self closing tags should only be used for [void elements](http://www.w3.org/html/wg/drafts/html/master/syntax.html#void-elements).  In HTML5 `<span/>` means `<span>` (since the `/` is ignored) not `<span></span>` as it does in XHTML.