feat: Adds --list and -p/--preset options for molr prepare
A default presets.yaml is used to read presets from. A user defined file can be specified in the .molrrc in the section [presets] and the key "path_to_presets".
Argparse parser has been extended with manual checks to make -p/--presets mutually exclusive with -f/--functional and -b/--basis-set.