Search parent directories for collection file

[LucasPickering]

Description

Describe the change. If there is an associated issue, please include the issue link (e.g. "Closes #xxx"). For UI changes, please also include screenshots.

• If a collection file isn't found in the current directory, recursively search our parents (up to the fs root) to find it.
• Print a notification on startup to show the loaded collection file (similar to what shows after a reload)
• In dev mode, always use the crate root to locate data/ instead of the cwd

Closes #194

Known Risks

What issues could potentially go wrong with this change? Is it a breaking change? What have you done to mitigate any potential risks?

Could potentially be unexpected behavior. Mitigated via documentation.

QA

How did you test this?

• cd src
• cargo run
• Confirm it loads the collection file and shows it in the parent
• Confirm logs are written to data/log/slumber.log in the crate root, not src/data/...

Checklist

• Have you read CONTRIBUTING.md already?
• Did you update CHANGELOG.md?
  • Only user-facing changes belong in the changelog. Internal changes such as refactors should only be included if they'll impact users, e.g. via performance improvement.
• Did you remove all TODOs?
  • If there are unresolved issues, please open a follow-on issue and link to it in a comment so future work can be tracked