Group notice attachment support

[Madpeterz]

Is your feature request related to a problem? Please describe.
The current group notice command does not support adding an attachment to the notice

Describe the solution you'd like
add an optional arg to the command where you can pass an inventory UUID to send with the group notice

Describe alternatives you've considered
1: Use a object to force send it
(Slow, requires uuid of group members no command to get uuids of group members right now)

[Madpeterz]

96d4d10