Convert Scan Task endpoints into python

[aloftus23]

🗣 Description

• Adds 3 new endpoints to views.py
• Adds get_tag_organizations to auth.py
• Created a new api_method and schema file

💭 Motivation and context

Convert backend to python.

🧪 Testing

Passes pre-commits and matches the output of the typescript endpoints. Need to write unit tests still

✅ Pre-approval checklist

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

✅ Pre-merge checklist

• [x] Revert dependencies to default branches.
• [x] Finalize version.

✅ Post-merge checklist

• [x] Create a release.