chore: clean up frontend pages

[hanlinc27]

Notion ticket link

Clean up Starter Code FE

Implementation description

• Removed unused route constants on FE
• Remove unused pages on FE
• Removed unused CRUD components (i.e. create form, display entities)
• Remove unused hook example
• Remove unused utility functions (i.e. CSV Export etc.)
• Replaced some of the semantic HTML with Chakra components

Steps to test

1. Pull branch, docker compose down
2. docker compose up
3. Check everything renders fine and there are no console errors

What should reviewers focus on?

• Make sure everything removed can be removed

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• I have run the appropriate linter(s)
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR