GitHub actions checks are failing

[andrewjbe]

The R-CMD-check and test-coverage GitHub actions are failing. I think it's just because GitHub Actions has no way to access the database.

I think we can fix this if we:

1. Create new database credentials for GitHub actions
2. Make those into secrets for the repo (see https://docs.github.com/en/actions/security-guides/encrypted-secrets and https://stackoverflow.com/questions/65926899/how-can-i-get-an-r-environment-via-sys-getenv-with-github-actions-using-secret)
3. Convert the SSL certs into base64 strings and add those as repo secrets as well (see https://stackoverflow.com/questions/67686405/how-to-store-and-use-ssl-tls-certificates-for-authentication-in-github-actions)
4. Add the secrets in our .yaml files so that GitHub actions can connect to the db and successfully run all the tests, etc.

[brancengregory]

This strategy is perfect, let's move forward!