Provide default bond energies (dissociation energy in Classic MW)

[#56525850]
Pass more data for plugins, let them modify output state (e.g. PE, KE)

[#56525850]
Implement simplest bonds creation due to chemical reaction

[#56525850]

TODO FIXME: there is small energy conservation problem. Bond's
chemical energy and bond strength are taken into account, so it's
something different.

After investigation it seems like NextGen and Classic MW treat LJ
potential between bonded atoms differently (but I have to double-check
it).