Enable reward for activity in GitHub discussion

[bodhish]

We should save events when a user marks an answer as solution for his question.
The one who answered the question will get a new event that says `Resolved a Question in the community'

This will enable a new badge Empathy

[khavinshankar]

@bodhish It seems there is no REST API support for GitHub discussions (community/community#4327), should we use GraphQl?

[bodhish]

They are going fully graph, I think we should explore porting it fully into graph.

[rithviknishad]

Closing as completed in #463