Allow dashboard panels to be found by monogram

Summary:
Just add the monogram to the datasource's name field
so that it will match when typing Wnn in the typeahead field.

Test Plan:
Tested locally on my dev phab. Try searching for a panel
by monogram in the 'Add existing panel' dialog on the
'arrange workboard' interface.

Previously: typing W123 showed no results.

After this change: typing W123 finds the panel W123

Reviewers: chad, epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D18121