Allow scroll scoreboard(64 players)

[Bamcane]

This PR is for solving #1828 , and not the same as DDNet, use 'w' (default) to scroll the scoreboard, and i test it, it could work

[Bamcane]

The "w" is the best button to scroll it, and we could scroll the scoreboard while playing.
Why don't use 'S'? I think that because of DDNet use it to active aimline as the default, if someone that new 0.7 players but DDNet players, 'S' is not a good button for them.