Menu - Adds support for Experimental UI section which includes the

new navigation structure in it's current state.

This commit does not reflect the final state of the menu, as there
are current and potential future usability issues to address. What's
included:
 - ability to turn experimental UI on and off per user
 - new navigation structure in experimental mode
 - modified navigation rendering for experimentation
 - tests for new navigation rendering

This does not include the new table view for systems - that will follow after this is accepted to be included as part of the experimental section as new parts of it are created.

Dependency - requires a new build of Alchemy after merging