ddd's modified Darceno's Minecarts

This is a modified fork of the original datapack Darceno's Minecart's, which is licensed under MIT.

There are a couple things that I wanted to remove and add. Idealistically, the changes are minimal, and the principle of faster minecart speeds are the same. Here is a list of changes from the original datapack:

• Added condition that tracks must be on gravel in order to have faster minecart effect (based on track ballasting in real life).
• Removed chunk loading capabilities (due to possible /forceload chunk leak)
• Removed modified powered rail recipe, reverting back to the vanilla recipe.

!gravel difference