Feature/install opentripplanner

This is definitely worth some discussion. With `nyc-trees` I'm using inventories that are associated with `group_vars`. I think it ends up playing out differently than what you're suggesting:

Development inventory: https://github.com/azavea/nyc-trees/blob/develop/deployment/ansible/inventory/development
Development variables: https://github.com/azavea/nyc-trees/blob/develop/deployment/ansible/group_vars/development