Show longest/current winning streak

[jamesremuscat]

Player stats should include their longest and current winning and losing streaks.

For these purposes:

• A game is won if more goals are scored than the opponent. Draws or point gains do not count as wins.
• A game is lost if fewer goals are scored than the opponent. Draws or points losses do not count as wins.
• Streak should be measured in games - winning once then not playing for a year does not count as a year-long winning streak!
• A player who has only won a single game in their career has a longest winning streak of 1.
• Later streaks should be preferentially displayed to older streaks of the same length (e.g. strictly it's a "most recent longest streak")

[jamesremuscat]

Originally raised by cjm.