Add option or default to search over 'regulates' for 'Filter by Term' for models

[hattrill]

The 'Filter by Term' search on the landing page does not search over the 'regulates' relation, which can result in models being missed.

So, searching with the term 'regulation of TOR signaling' retrieves 101 models, but 'TOR signaling' only retrieves 72 (and these are not all overlapping).

Would be useful to either have an option to 'include regulates' or just do this by default.