CORE-5072 Added Advanced Sharing and Copy Link buttons.

Added download URL keys to the DataLink AutoBean interface.
Refactored the "Copy" button in the DataLinkPanel into a "Copy Link" and "Advanced Sharing" button.
The "Copy Link" button now uses the "download-url" value from DataLink models.
The "Advanced Sharing" button will open the "download-page-url" in a new window.
Refactored the DataLinkPanelCell to use the "download-page-url" for displaying links.
Refactored the DiskResourceNameCell to use the "download-url" for copying links.
Minor logic refactor in the DataLinkPanel::TreeSelectionHandler.
CORE-4960
CORE-4876
CORE-4876
CORE-4876
CORE-4876
CORE-4876: Fleshing out unit tests for search UI
CORE-4876: Continuing search-related unit test dev
CORE-4876: Ongoing unit test development
CORE-4876: ongoing unit test dev
CORE-4976
CORE-4876: Unit tests for DataSearchPresenter have 100% coverage
CORE-4876: Integrated search service facade with FolderContentsRpcProxy
CORE-4876: Removed data search history impl
All previous data search history implementations have been removed. FolderContentsRpcProxy is now the only class which will submit search queries. All unit tests are passing.
Ongoing
CORE-4876: Most UI/presenter tests in place. Still need to test search field and define service level contract