Nucleic acid sub residue selection

[sverhoeven]

Is your feature request related to a problem? Please describe.
Currently you can select a whole base as the active residue. It would be nice if you could select atoms either individually or as set like backbone or sidechain.

Describe the solution you'd like
A clear and concise description of what you want to happen.

Describe alternatives you've considered
Downloading tbl file and making manual edits.

Additional context
In https://www.bonvinlab.org/education/HADDOCK24/HADDOCK24-protein-DNA-advanced/#available-data

The AIRViewer.py in the training material has selection implemented

		self.NAmajor = {'THY':'name H3 or name O4 or name C4 or name C5 or name C6 or name C7',
		   				'ADE':'name H61 or name H62 or name N1 or name N7 or name C5 or name C6 or name C8',
		   				'GUA':'name H1 or name H21 or name N7 or name O6 or name C5 or name C6 or name C8',
		   				'CYT':'name H41 or name H42 or name N3 or name C4 or name C5 or name C6'}
		
		self.NAminor = {'THY':'name H3 or name O2 or name C2',
		   				'ADE':'name N1 or name N3 or name C2 or name C4',
		   				'GUA':'name H1 or name H21 or name H22 or name N3 or name C2 or name C4',
		   				'CYT':'name N3 or name O2 or name C2'}
	
		self.NAbase = {'THY':'name H3 or name O2 or name O4 or name C2 or name C4 or name C5 or name C6 or name C7',
					   'ADE':'name H61 or name H62 or name N1 or name N3 or name N7 or name C2 or name C4 or name C5 or name C6 or name C8',
					   'CYT':'name H41 or name H42 or name N3 or name O2 or name C2 or name C4 or name C5 or name C6',
					   'GUA':'name H1 or name H21 or name H22 or name N3 or name N7 or name O6 or name C2 or name C4 or name C5 or name C6 or name C8'}
	
		self.NAsugar = "name C1' or name O4' or name C2' or name O3' or name O5' or name P or name O1P or name O2P"