Improve logging

[jwodder]

• Log the bodies & "Depth" headers of all accepted PROPFIND requests
• Log PROPFIND requests rejected due to infinite or invalid "Depth" headers
• Log PROPFIND requests rejected due to invalid request bodies
• Log all errors (with cause chains) that result in 5xx responses (Log errors that cause 404 & 500 responses #63)
• Log the reasons for 404 responses
  • Log errors that reach the top level and result in 404's (Log errors that cause 404 & 500 responses #63)
  • Log all errors that are converted to 404's before reaching the top level
  • Log 404's caused by a function returning None
  • When a request is received for an invalid/unrecognized path, log that this is what is happening
• Log all Dandi Archive API requests (Improve logging configuration #58)
• Log all S3 requests
• Try to improve the log display format?
• Enable tracing for moka (which uses log)
  • Problem: Using `LogTracer` with a tracing subscriber tokio-rs/tracing#2875
• Do not log SSL details for HTTPS requests made by the server (Improve logging configuration #58)
• Use tracing-unwrap to log failed unwraps/expects?