Make best pings green, good pings yellow, medium pings orange and worst pings red in scoreboard

Small cosmetic change.

Since bad pings (>80) increasingly show as red in the scoreboard, this makes it so good pings (<80) increasingly show as green in the scoreboard. In my humble opinion it looks nicer and it's also consistent with the multiplayer server list.

Dr. Jaska: The bikeshed is now fully customizable via:

hud_panel_scoreboard_ping_best_milliseconds 0 "the value for the best ping value"
hud_panel_scoreboard_ping_medium_milliseconds_milliseconds 70 "the value for medium ping value"
hud_panel_scoreboard_ping_high_milliseconds 100 "the value for high ping value"
hud_panel_scoreboard_ping_worst_milliseconds 150 "the value for worst ping value"
hud_panel_scoreboard_ping_best_color "0 1 0" "the color for best possible ping values"
hud_panel_scoreboard_ping_med_color "1 1 0" "the color for medium ping values"
hud_panel_scoreboard_ping_high_color "1 0.5 0" "the color for high ping values"
hud_panel_scoreboard_ping_worst_color "1 0 0" "the color for worst ping values"