Lammps-step

* Avoided using centroid/stress/atom for heat flux in standard NVE, NVT, ... dynamics
with Class 2 forcefield.
* Added option to not use centroid/stress/atom for any forcefield.

* centroid/stress/atom does not work with Class 2 forcefields, so don't use for PCFF.

* Added trajectory panel to support diffusion, viscosity and simple thermal
conductivity.
* Added support for separate GPU versions of LAMMPS.
* Added support for command-line arguments to LAMMPS, mainly used for accelerators.
* Added support for using modules.

* Internal changes to support thermal conductivity with its embedded flowchart.
* Added the heat flux substep.
* Now delete output and reference files when rerunning, so the output is clean.
* Internal changes to support running LAMMPS from a Python driver.
* Corrected units of properties returned from LAMMPS when e.g. metal units used.
* Added support for Buckingham potentials
* Fixed issues with and cleaned up the use of hybrid types for bonds, angles, ....
* Fixed issues with the alignment of some of the widgets in the GUI.

* Importing pymbar timeseries writes a warning to the terminal about its proper
usage. SEAMM already handles the warned case, so the message is simply confusing to
users and hence this release hides it.

2023.4.6 -- Better forcefield handling.
* Added correct molecule numbers for valence forcefields.
* Correctly handle ReaxFF from OpenKim
* Updated for some minor changes in OpenKim

* Added handling of the OPLS-AA forcefield
* Moved documentation to new MolSSI theme and diátaxis layout
* Cleaned up internale dependencies and workflows for GitHub