[iOS] Convert AboutChromeCollectionVC to TableView

This CL converts AboutChromeCollectionViewController to use TableView
instead of collection view.
It also updates the VersionItem to be displayed as a cell instead of as
an item. It means that the callback when the version is tapped cannot
happen in the VC. So the cell has a button copying the version to the
pasteboard when tapped.

Bug: 894791
Change-Id: I6cdae4b09235bb6f72e2dbffac88a5dd9f78e67a
Reviewed-on: https://chromium-review.googlesource.com/c/1291390
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602350}
12 files changed