Move log file again

[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.

• Move logs back into a single predictable file
• Rotate log files
  • If the size exceeds 1MB, it'll be moved to a backup, so we max at 2MB usage
• Don't crash if we can't log
• Remove --log flag since it's unnecessary now
• Update docs to reflect new reality

The --log removal is a breaking change, but in reality it's not going to break anyone's workflow.

I'd like to add the PID to the log message, but that requires tokio-rs/tracing#2655 (or at least it makes it a lot easier)

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?

• Bugs bad
• Logs are harder to disambiguate now. Will be mitigated in the future by including the PID

QA

How did you test this?

Manual testing

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