LP#1831788: create CommonWidgetsModule

LP#1831788: create CommonWidgetsModule

This patch moves some commonly-shared components off to a separate
module. The immediate motivation is to avoid circular dependencies
when adding filtering widgets to eg-grid.

Components included in CommonWidgetsModule should be "core" in the
sense that they are unlikely to ever need to embed one another.

Sponsored-by: MassLNC
Sponsored-by: Georgia Public Library Service
Sponsored-by: Indiana State Library
Sponsored-by: CW MARS
Sponsored-by: King County Library System
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>
Signed-off-by: Bill Erickson <berickxx@gmail.com>