Adds White House logs search

Adds the ability to search for:
* "Who visits the White House?"
* "Who did Robert Woodward visit at the White House?"
* "When did Chris Christie visit the White House?"
* "How many times has Beyonce Knowles been to the White House?"
* "Did Sheldon Adelson visit the White House?"

Borrows heavily from bill search and queries the White House visitor access release API.