Web-App: Configure search for both events and legislation from single query

[evamaxfield]

Once https://github.com/CouncilDataProject/cdp-backend/issues/81 is complete we will be able to fire off a search for both events and for matters from plain text. This will mean we will need to add functionality for completing that search and additionally adding functionality for merging the two result sets somehow (if we decide to go down that route)