add docs

docs/_config.yml

docs/_toc.yml

docs/api/core/core_objects.md

docs/api/core/index.md

docs/api/core/model.md

docs/api/core/sim_config.md

docs/api/index.md

docs/api/interaction_potentials/ibi.md

docs/api/interaction_potentials/index.md

docs/api/interaction_potentials/interactions.md

docs/api/polymer_modeling/fjc_polymer_model.md

docs/api/polymer_modeling/hps_polymer_model.md

docs/api/polymer_modeling/index.md

docs/api/polymer_modeling/kh_polymer_model.md

docs/api/polymer_modeling/mpipi_polymer.md

docs/api/polymer_modeling/onck_polymer_model.md

docs/api/polymer_modeling/polymer.md

docs/api/polymer_modeling/sali_polymer_model.md

docs/api/polymer_modeling/ssdna_two_bead.md

docs/api/rigidbody_models/index.md