Fix two major bugs

Add mach and kinetic energy as units

This is a major update that improves the performance and accuracy of this plugin significantly.

It supports v1.16 to 1.21.4 and beyond

/as restart and /as forceshutdown have been removed

- Add config key to control if speedometer is on by default
- Speedometer is now enabled by default
- Add help menu
- Add /as help and /as show and /as hide as aliases

The following things have been added in this cumulative update:

• Update to 1.20 - 1.20.4
• Backwards support 1.16-1.20.4
• Add config file to configure runinvehicles and destroydataonplayer leave
• People with admin perm can now control other people

Lots of new features