Exploded view

[martinRenou]

Fix #38

TODO:

• Fix annotations positions in exploded view
• Added UI controls for enabling/disabling the exploded view and changing its factor
• Sync exploded view state with other clients (for the follow mode) won't do
• Fix pointer position by taking the exploded view into account
• Update exploded view when mesh visibility changes
• Update exploded view when mesh removal change?

[github-actions]

👈 Launch a Binder on branch martinRenou/jupytercad/exploded_view

[martinRenou]

• Fix annotations positions in exploded view
• Fix pointer position by taking the exploded view into account

Those two points require that the annotations and pointer are attached to a specific mesh, in order to know how they should be exploded. So I need to change a bit the models of pointers and annotations.

[martinRenou]

The last two commits make the 3D pointers aware of the picked mesh, this allows showing the collaborators pointers at the correct position whether we are in exploded view or not:

(right side is picking: left side is showing the right picked position relative to the selected mesh)

[trungleduc]

Thanks @martinRenou, it looks great!