Supports Minecraft from 1.20 to 1.21

Added backwards compatibility with 1.20
Now playtime add|remove and playtimegroup commands support multiple time formats at a time
Added possibility to specify seconds when adding or removing the playtime
Fixed startup crash when luckperms was not installed on the server
Fixed playtimegroup removeGroup subcommand


Fix from 3.0.2:
Updated playtime add|remove commands to reflect correct changes even with low tps
Fixed artificial playtime so it now doesn't get added/removed from actual playtime after every login
Now artificial playtime is taken into consideration for playtimeaverage, playtimepercentage and playtimetop commands