Throughout: Use event_report!() macros for reporting Errors.

I identified the cases to replace by searching for the string .report(). There are a few that I didn't change:

• A couple of cases that used anyhow::Error,
• One case that reported two Errors.
• Two cases in tor_hsclient::err that just did error!("Bug: {}").

I have also not audited the cases in tor-hsclient where we're using tor_error::Report manually.

Nonetheless, closes #949 (closed).