Add new /greport answer marks
## Proposal
Through my experience with ``/greport`` I have found a type of gaps within the existing system, where the investigating admin is forced to pick an unsuitable answer mark out of a limited collection. To solve this I propose to add new answer marks that suit various needs. I believe that this will help both admins and reporters.
## ``discuss``
* Purpose: The admin has investigated the greport, but has decided that further discussion with the reporter is needed.
* Mail message: ``XXXX has investigated your greport, but further discussion is needed. Contact XXXX to resolve the issue.``
## ``unknown``
* Purpose: The admin has investigated the greport, but didn't have enough info to make a conclusion.
* Mail message: ``XXXX has investigated your greport, but they couldn't come to a conclusion.``
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