Option to scale certain match scores by a certain factor

[samjmartin04]

It would be good to be able to scale a certain subset of matches (e.g. from the virtual competition) by half so that they are worth less than the rest of the league.

This is desired for SR2025 virtual league as this ensures that the virtual league is not worth too much. In the rules, we said that the virtual league would be 20-25% of the whole league. The in-person league is going to be 7-8 matches per team, so we need 2 virtual league appearances per team or 4 virtual league appearances are scored such that they are worth half as much.