Show assignment atom numbers in the ranges

It is now possible to display the atom numbers on the molecule


It would be nice to also display this number of the ranges so that we can see how the molecule has been assigned and it can be directly place in reports.

There are different issues ...
1. A range may be associated with many atoms
2. When we assign a proton spectrum (most of the case) we can either assign the proton or the carbon (we don't always 'explode' the protons.
3. We need to find the atom number corresponding to the diaIDs and maybe save it in the .nmrium file
4. When loading a molfile we should very likely normalize it (recreate it using openchemlib) so that the atom numbers corresponds to the assignment and it could be used in other software).