Changes to player ranks, score, and game mode limits on scoreboard

More scoreboard changes, this time addressing how player ranks, score, and game mode limits appear.

1. The text colours used to colourize rank ordinals on the scoreboard (and large frag messages) now use more traditional colours used for 1st, 2nd, and 3rd place rankings (addresses https://zandronum.com/tracker/view.php?id=4385).

   • Blue to yellow or gold (1st)
   • Red to dark grey or silver (2nd)
   • Green to brown or bronze (3rd)

2. https://zandronum.com/tracker/view.php?id=4361 suggests that the "x things left" messages (e.g. "46 frags left") on the scoreboard are sometimes confusing in conjunction with showing a player or team's rank and score, and that static messages like "50 frags to win" are more desirable. Personally, I still like seeing how much score (frags, points, or wins) is left because then I immediately know how close a player or team is to winning. Thus, I added a new CVar, cl_showscoreleft, so players have the option to choose which format they like more.

3. https://zandronum.com/tracker/view.php?id=4372 also suggests that there should be an "x leads with y frags/points/wins" message on the scoreboard in non-team game modes when the local player is a true spectator and not spying on another player. It'd also be cool to show this during intermissions to see who won the game, or how many players are tied. This message appears in different ways, also depending on whether we're in an intermission or not:

   • "x leads/won with y things": when somebody is taking the lead or won.
   • "all/both {or x} players are/have tied at y things": when multiple players are tied for the lead.