feat: SCHWED-5783 accept ligands as input

modules/mol/alg/pymod/ligand_scoring.py

modules/mol/alg/tests/test_ligand_scoring.py

modules/mol/alg/tests/testfiles/1r8q.pdb.gz

modules/mol/alg/tests/testfiles/1r8q_ligand_0.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_1.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_2.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_3.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_4.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_5.sdf

modules/mol/alg/tests/testfiles/1r8q_ligand_6.sdf

modules/mol/alg/tests/testfiles/1r8q_protein.pdb.gz

modules/mol/alg/tests/testfiles/P84080_model_01.cif.gz

modules/mol/alg/tests/testfiles/P84080_model_01.pdb

modules/mol/alg/tests/testfiles/P84080_model_02.pdb

modules/mol/alg/tests/testfiles/P84080_model_02_ligand_0.sdf

modules/mol/alg/tests/testfiles/P84080_model_02_nolig.pdb

...es/mol/alg/tests/testfiles/P84080_model_02_protein.pdb.gz

modules/mol/alg/tests/testfiles/P84080_model_03.cif.gz

modules/mol/alg/tests/testfiles/P84080_model_03.pdb

modules/mol/alg/tests/testfiles/P84080_model_04.cif.gz