Improve the CI/CD pipeline credential flow

[rivernews]

Reduce redundancy and avoid setting the same environment variable or secret at multiple different places.

Quick look at current credential storage

Where are the credentials now?

Location	Format	Contents
secret-management repository	JSON -> AWS SSM	Django, Database, AWS, DO, Dockerhub
iriversland-public repository	Local .py	AWS (S3), Database, Django Misc
terraform-provisioning repository	Local .tfvars	Database (backend storage), DO, AWS, Dockerhub
CircleCI iriversland-public	ENV VAR in portal	AWS, DO, Django, Dockerhub, Database, Database (TF backend storage), Terraform env var (for credential)
CircleCI terraform-provisioning	ENV VAR in portal	Database (TF backend storage), Terraform env var (for credential)

What kind of credentials used are there?

• Django app itself, etc, SECRET_KEY, also gmail
  • Including database - on heroku
• AWS. Used across multiple stacks, like for S3, for secret management SSM, for external DNS Route53.
• Dockerhub

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