[ Feature ] Add configurable minecart speeds with signs

[zndrmn]

Add a way to change the speed of minecarts in game with the use of signs. something like this server side mod https://www.curseforge.com/minecraft/mc-mods/speed-carts

[zndrmn]

also server sided config with min and max minecart speeds would be nice

example: min 8 - max 32 / min 1 - max 128 etc player can only choose speeds within that range in game

[Patbox]

Instead of signs, it's implemented with new rail type