Add Default Policies [#624]

[pattisdr]

❗ Contains data migration; check downrev before merging

Purpose

Ship Fidesops with two default Policies: download and delete so Fidesops instances can run privacy requests right away.
The policies are created as a data migration.

Changes

Adds a data migration that:

• Creates a local StorageConfig
• Creates a Client with a specific fides_key
• If a download policy does not exist, create one, with a Rule using the localstorage and the the RuleTarget looking at identifiable data, with the autogenerated client above
• If a delete policy does not exist, create one, with a Rule that using a string masking strategy, targeting identifiable data, with the autogenerated client above
• Reverse migration only removes the download/delete policies and their associated resources if they were created by the autogenerated client.

Note: this does not create resources in test mode (pytest)

Checklist

• Update CHANGELOG.md file
  • Merge in main so the most recent CHANGELOG.md file is being appended to
  • Add description within the Unreleased section in an appropriate category. Add a new category from the list at the top of the file if the needed one isn't already there.
  • Add a link to this PR at the end of the description with the PR number as the text. example: #1
• Applicable documentation updated (guides, quickstart, postman collections, tutorial, fidesdemo, database diagram.
• If docs updated (select one):
  • documentation complete, or draft/outline provided (tag docs-team to complete/review on this branch)
  • documentation issue created (tag docs-team to complete issue separately)
• Good unit test/integration test coverage
• This PR contains a DB migration. If checked, the reviewer should confirm with the author that the down_revision correctly references the previous migration before merging
• The Run Unsafe PR Checks label has been applied, and checks have passed, if this PR touches any external services

Ticket

Fixes #624

[eastandwestwind]

Couple questions related to docs:

1. Should we add to docs somewhere that these Policies are already created by default, to avoid confusion?

Some places in docs where this might make sense- https://ethyca.github.io/fidesops/postman/using_postman/

https://ethyca.github.io/fidesops/guides/policies/

2. test mode / dev mode do diff things and can be confusing to someone first looking at config vars. I think it would be useful to better clarify in docs what setting these vars actually do, perhaps in a separate PR.

[pattisdr]

Thanks @eastandwestwind I'll look into clarifying these items in the docs

[pattisdr]

@ethyca/docs-authors minor docs added to describe the two autogenerated policies that ship with Fidesops and clarify that the TESTING variable is set by Pytest for when we run unit tests.

[eastandwestwind]

Thanks @pattisdr , thumbs up from me!