[ENHANCEMENT] Change syntax for a few commands

[diademiemi]

The addborder and removeborder commands should be moved into one border command with border add and border remove.
The same should be done for addcheckpoint and removecheckpoint
Checkpoint should be slightly different since new commands will be added in #21.
The command will be checkpoint add & checkpoint 1 remove.
This clears up room to move a few options into the main command.
option teleport should be moved to the main command.
option illegalarea should be for start lines, and option laps should be for finish lines.
option maxwinners should be renamed to winners and put in the main command.

ln config maxwins and ln config forget should be moved into one subcommand.
ln config maxwins amount <number> and ln config maxwins forget <username/uuid/all. This clears up the purpose for the forget command.