Medical imaging on toolshed

[Zach Pearson]

Our most recent NIAID contract asks us to explore putting ChimeraX's medical imaging functionality on the ChimeraX Toolshed. The rationale for this change is that, by putting medical imaging on the toolshed, a user who downloads that bundle is opting into an experience of ChimeraX that differs or may differ radically from its conventional use. It gives that bundle extensive leeway to, among other things, reconfigure the user interface to remove biological shortcuts that may not be of use in a medical setting and replace them with new shortcuts that would be.

[Zach Pearson]

The ability to remove buttons from the toolbar is currently TODO'd in ui/src/tabbedtoolbar.py, and that's kind of a blocker for getting this done because the medical imaging bundle would need to be able to clear and repopulate the toolbar.

[Zach Pearson]

#14906 would also be nice to have but isn't really a blocker since the medical toolbar can just have a button that switches between modes.

[Zach Pearson]

This doesn't need to be milestoned.