Use toml-f parser to read parameters.toml

[TyBalduf]

Currently parameters.toml is really only usable from the Python API. While ATM and MBD parameters are listed here for a number of functionals, only the ATM ones are available in the Fortran code (and by extension the C API) and they are hard-coded rather than being read from parameters.toml.

toml-f seems like it is ready for use and would allow us to parse this parameter file, rather than just use it as a reference database.

[awvwgk]

An implementation could be borrowed from s-dftd3: https://github.com/dftd3/simple-dftd3/blob/main/app/toml.f90