create roadmap for integrating clayff

**Is your feature request related to a problem? Please describe.**
This issue is centred around creating a roadmap for adding the CLAYFF force fields to MDMC. The original paper for the CLAYFF parameters is J. Phys. Chem. B 2004, 108, 4, 1255–1266 (https://doi.org/10.1021/jp0363287).

**Describe the solution you'd like**
Create issues that need to be implemented/resolved to successfully add CLAYFF. This should include at a minimum issues for:
- adding a clayff force field class
-(if required: add a clayff data file containing the parameters)
- implementing an experimental data file to compare against, e.g. paracetamol data taken from IRIS
- (if required: add a reader for the experimental data file format)
- add a tutorial for clayff
- add unit/system tests for any new functionality
- add any required documentation

**Additional context**
This is part of the Master project work of @martinhp27.