Required for the swoole metrics scraping.

Rebased

Rebase

Rebased

https://git.kolab.org/D5493

This doesn't work because of

In D5490#71580, @machniak wrote:

It makes it more standard if we use 204 when the reply is indeed empty. So, it might make sense to use both 200 and 204 according to the response body being empty or not. Also, the header name might be better as X-Kolab-Mailfilter-Action.

Changed header name

fixup

At least we ended up with roughly the same solution ;-)

I suppose we also have to allow aliases, so we just allow everything.

probably needs a test adjusted someplace.

Allows noreply@ to send notifications for users.

It would be good to have a "why" we don't want the button to depend on the plan mode as part of the commit description.

Cleanup

The reinjection didn't actually work without converting back to LF only, not sure why.

I do have a second part to the patch that catches the exception, and returns CODE_ACCEPT_EMPTY instead in order to not halt mail delivery, but then again, we should never run into this I think.