Error when setting up API server for local development

[ameyagodbole]

I wanted to raise an issue about errors when doing a fresh installation of the repository.

At this step in the start.md setup instructions, when running python install.py several issues arise.

1. api/common/config.py already exists, so the script never asks for the DB information and paths i.e. this point in the code is never reached
   • I got around this by explicitly setting the values in api/common/config.py
2. api/common/config.py and evaluation/eval_config.py expects several environment variables (such as AWS credentials) to be set. This is a very strong requirement for a fresh install
   • I have temporarily bypassed this by changing all dictionary look-ups [] to .get() operations in those files