Implement GitHub environments for deployment

[SarahJohnsonONS]

Right now we have a CI/CD process where we don't use environments, and have secrets are generally in actions.

For example,

Private Zenhub Image

We need to figure out whether we want to adopt an environment process to store secrets and/or remove the necessity of some of them.

Instructions: Targeting different environments

Goal of this ticket: recommend adopting environments or not, recommend adopting new ways of authenticating to pypi across the board, write a ticket for implmentation accordingly.