Support the gin theme

Problem/Motivation

Workbench works with Gin, but does not appear in the Gin Toolbar, which makes tabbed navigation broken

Steps to reproduce

Enable Gin and Gin Toolbar -- the Workbench element will be links in the right side, not in the Gin Toolbar.

Proposed resolution

Support Gin Toolbar.

Remaining tasks

Figure out what is needed.

User interface changes

Moves the Workbench menu into Gin Toolbar.

API changes

None expected

Data model changes