Port player.ping from SRB2Kart

!1786 (closed) tried to fit this into their merge but it was inactive.

This should help with players making custom leaderboards without relying on player.cmd.latency formulas.

This is also client sided, so dont try to work this with synched things.

Thank you James R.

Compiled Build Jun 20 2023: srb2win_ping.exe