[FEAT] Use configuration validation patterns for environment based config

[belthesar]

Is your feature request related to a problem? Please describe.
TAU currently assumes that configuration received via environment variables will match the intended behavior. This can lead to silent failures, especially when deploying outside of application defaults, which assume a local deploy with Ngrok.

Describe the solution you'd like
In support of good documentation in both code and readmes, TAU should validate config, and raise exceptions as needed to inform the user deploying TAU of any issues where config is not in spec.

Describe alternatives you've considered
Documentation alone could be used to handle this in lieu of validating config, but will lead to silent errors / magic behavior.

Additional context
Consider using django-environ and/or environs to handle environment variable parsing instead of the existing use of os.environ