Add results matrix visualisation for tournaments #14
Description
In all-vs-all tournaments, a nice visualisation of the results is a matrix (players listed across top & down left, each cell corresponds to the result of the match between those players)
- Axis of entry vs self should be empty
- Either keep one half blank, or duplicate data across divide (but inverted); no need to run matches of A vs B and B vs A.
- Requires drill-down capability into matches