fix(imip): add context to imip log messages

[kesselb]

Summary

Making the log messages regarding imip processing more useful by including additional context.

Examples of the current state / without this patch

{
  "reqId": "...",
  "level": 2,
  "time": "...",
  "remoteAddr": "",
  "user": "--",
  "app": "no app in context",
  "method": "",
  "url": "--",
  "message": "iMip message event could not be processed because recipient and ORGANIZER must be identical",
  "userAgent": "--",
  "version": "...",
  "data": []
}
{
  "reqId": "...",
  "level": 2,
  "time": "...",
  "remoteAddr": "",
  "user": "--",
  "app": "no app in context",
  "method": "",
  "url": "--",
  "message": "iMip message event dose not contains an organizer",
  "userAgent": "--",
  "version": "...",
  "data": []
}
{
  "reqId": "...",
  "level": 2,
  "time": "...",
  "remoteAddr": "",
  "user": "--",
  "app": "no app in context",
  "method": "",
  "url": "--",
  "message": "iMip message event does not contain a attendee that matches the recipient",
  "userAgent": "--",
  "version": "...",
  "data": []
}

TODO

• Manual testing

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[kesselb]

It might be useful to know the sender/recipient. But principalUri and event UID (if applicable) might be enough for a start.

Context: The code is processing an imip message. That might be an reply from an external person for a calender invitation or a locall user sending out invitations.