feature: add pingparticipants and pingothers commands

[iamgiolaga]

Discussed in #7

^{Originally posted by iamgiolaga November 12, 2022}
It would be useful to have two additional commands:

• pingparticipants: to tag all the participants in order to have their attention on useful information regarding the incoming match
• pingothers: to tag everybody in the group that is NOT a participant (typical use case is to remind them if they want to participate to the next game)

[iamgiolaga]

pingparticipants: to tag all the participants in order to have their attention on useful information regarding the incoming match

maybe useless this because you achive the same by using /participants