Transition Micromasters from Heroku Managed Postgres to Pulumi Managed RDS

[feoh]

Description

This pull request contains the necessary Pulumi code and documentation to migrate the micromasters project from Heroku hosted Postgres to Amazon AWS RDS.

Motivation and Context

This pull request fixes #1090 and enables the migration of Heroku hosted Postgres to AWS RDS under management by Pulumi.

This represents an ongoing cost savings as well as a decrease in operational burden since the current Heroku hosted DB is largely managed manually.

How Has This Been Tested?

As per @pdpinch I browsed the following URLs in my browser and ensured that each loaded properly including proper layout, images and textual information.

https://micromasters-ci.odl.mit.edu/
https://micromasters-ci.odl.mit.edu/dedp/
https://micromasters-ci.odl.mit.edu/scm/
https://micromasters-ci.odl.mit.edu/cms/
https://micromasters-ci.odl.mit.edu/admin/
https://micromasters-ci.odl.mit.edu/learners/
https://micromasters-ci.odl.mit.edu/dashboard/

I used equivalent links for QA/RC.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• [ x] Enhancement (improves on existing behavior)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project. (Did you install and run the pre-commit hooks?)
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[blarghmatey]

Overall looks good! A couple of minor notes, but otherwise should be ready to go. It does look like some unrelated changes from main branch got included so it might be worth a rebase to clean up the diff.

[Ardiea]

🎉 💯 🥇