Implicit member removal happens without any notification

[link2xt]

For member addition we have "member added" info messages visible even on implicit addition without mentioning who added a member.

But recently I had a case when member was implicitly removed from the chat, writing a day ago without "~" (member not part of the group indication) and then next day was not in the member list, without any notice. This was caused by someone else who did not previously receive messages for some time because of broken mail server setup.

Long story short, I think there should be messages about implicit member removal in addition to messages about implicit member additions e.g. if the whole memberlist is recreated.

[iequidoo]

A related PR, but about an implicit addition of SELF: #6205.
EDIT: Implemented on top of the existing commit in #6205 to avoid merge conflicts.