Add "addRadialBond" event to modeler's dispatcher

[#41092127]
Calculate disulphide bonds in the MD2D engine

[#41092127]
Detect in modeler when a new disulphide bonds is created

[#41092127]

Also dispatch a special event to notify the view.
Visualize disulphide bonds in a special way (yellow color)

[#41092127]

Note that this work also includes a small refactoring of radial bond
styles and a new SASS file. This file is intended to contain CSS
styles of elements managed by molecule-container, which can be defined
statically, without JS.

Probably it can be a good idea to move there as much as it's possible
to make visual tweaking of the simulation faster and easier.