Create a DashboardTable widget

The new DashboardTable widget was refactored out of the
CustomDashboardScreen so that it can be used by other
screens.  This will be used in the next change to
make a ProjectDashboardScreen which will inherit from a
ProjectScreen instead of a CustomDashboardScreen so that
it can be more consistent with the other ProjectScreens
(share menus,styling  etc...).

Change-Id: I2b461fd6b1675fa7afdd4cdc62d49f074119a08f