Add reviewer instructions

[IAlibay]

We need a set of instructions for reviewers of submitted inputs

[hannahbaumann]

Items for a checklist:

• directory structure and file names as in the template
• filled in system preparation details in the PREPARATION_DETAILS.md file
  • preparation details make sense and are sufficiently detailed to be able to reproduce it
• added a PDB file with the protein named protein.pdb
  • removed any cofactors from the PDB file and placed them in cofactors.sdf
  • kept cystallographic waters and metals in the PDB file
  • amino acids have the same protonation states as in the original structure prepped by Ross et al.
• copied over the ligands SDF file to a file named ligands.sdf and removed any duplicate binding modes or protonation states, keeping the more favorable state