Expose "withAnyProjects()" in the UI

Summary:
Add an "Any Projects" field to the custom search UI.

This is starting to get ugly but we'll do a design pass on it before toooo long.

Test Plan: {F20423}

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T1610

Differential Revision: https://secure.phabricator.com/D3632