Okta initial integrations

[nickviola]

🗣 Description

Initial Okta Integration logic

💭 Motivation and context

Integrate Okta as the primary authentication platform that is confiugred with new Cognito user pools.

🧪 Testing

Rebuild the latest changes on this branch, (APPLY DATABASE MODEL CHANGES FOR USER) on the login screen, click "Login with Okta", then use your PIV or email address to signup/login. Once logged in you will be redirected to the XFD Application as an authenticated user.

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.