[ENHANCEMENT] Quick trajectory operations for atom selection

**Is your feature request related to a problem? Please describe.**
To extend the selection capabilities of the new selection mechanism in https://github.com/ISISNeutronMuon/MDANSE/pull/672, additional operations on trajectories should be implemented:
1. Folding atoms into the box for the current trajectory frame,
2. Detecting chemical bonds (including periodic boundary conditions) for a single frame,
3. Making molecules continuous for the current trajectory frame.
This will have to be visualised in the atom selection dialog AND saved in the selection operations (since changing the current atom coordinates will have an effect on spatial selection).

**Describe the solution you'd like**
New selection operations should be added (which will change the positions ONLY for the purpose of selection), and the trajectory view should be updated accordingly.

**Describe alternatives you've considered**
Any suggestions are welcome.

**Additional context**
N/A

Start by reading PR #672 and the new selection mechanism it introduces, then trace the atom selection dialog and trajectory view mentioned in this issue. Identify how selection operations are stored and how a current trajectory frame is represented; the work is done when folding, bond detection with periodic boundaries, and molecule continuity are available for selection, reflected in the view, and preserved in the selection operations.

Written by the indexing model from the issue text.