Not configurable sender and other issues

Composer doesn't fully apply this patch anymore (applies partially and breaks the site)

I've re-rolled this patch, it was conflicting with the new maillog_nosend_notify setting.

I've also left off the portion of the patch that was rendering the log as HTML. The page looked very strange when it tried to render multipart emails. It looks like there is already an issue about rendering the emails in an iframe, that might be a safer option https://www.drupal.org/project/maillog/issues/3357920 ✨ Render HTML message in iFrame Needs work .

The last submitted patch, 6: maillog-n3176023-6.patch, failed testing. View results →
- codesniffer_fixes.patch Interdiff of automated coding standards fixes only.

Re-rolled patch and created merge request.