Change location of footer component from app.tsx to layout.tsx to correctly position footer Fixes #2545

[lfilip-ivaal]

🗣 Description

• Changed location of footer from app.tsx to layout.tsx
• Removed old footer code that no longer was applicable.
• Edit formatting CSS to put the footer at the bottom of the page after the content or at the bottom of the page if not enough content to fill the page. Fixes #2545

💭 Motivation and context

General UX change to not have the footer float up near the top if there wasn't enough content to push it to the bottom.

🧪 Testing

Manual testing.

✅ 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] All new and existing tests pass.

✅ Pre-merge checklist

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

✅ Post-merge checklist

• [ ] Create a release.

[lfilip-ivaal]

@lfilip-ivaal - there are test failures in this PR. Can you see if you can clean up those before we merge.

Looked into this and I needed to update the snapshot since the footer technically moved to a different location within the file structure.