Hide settings ui behind a URL parameter

[aminalhazwani]

It should be possible to hide dev-only settings like

or

so that research participants don't "stumble" on those when we use protowiki-powered prototypes during usability tests.

we could use a URL parameter to give access to those popovers.

[TodePond]

Notes for self:

• The second screenshot shows a dev menu that comes by default within the chrome header. We could add a setting (that could be auto-applied by a URL param) that disables it.
• The first screenshot shows a prototype-specific menu - not a default for protowiki, so it's a downstream issue. It could listen to the same setting if we had that in place.