Interop: Gromacs ITP files

[mattwthompson]

It might be nice to support writing out to ITP files, which could help against data explosion and the atom type compression problem.

https://manual.gromacs.org/documentation/current/reference-manual/topologies/topology-file-formats.html#molecule-itp-file

[IAlibay]

Just wanted to comment here, support for writing out ITP files would be hugely helpful from the OpenFE standpoint. Without them it becomes quasi-impossible to do topology-based alchemical transformations in gromacs (which is unfortunately the only way we can properly do alchemistry at the moment).