[+] - Added
[•] - Changed

[+] - Added /corona check <player> - command used for cehcking player's infection status
[+] - Added permission "corona.check.self" - Permission needed for checking your own infection status.
[+] - Added permission "corona.check.others" - Permission needed for checking other player's infection status.
[+] - Added PlaceholderAPI placeholder %MPCorona_check% - Shows the infection status of the player. Config messages "check infected" and "check not infected" are used for this placeholder.
[+] - Added command tab completer - for easier use of plugin commands.

[•] - Changed package names following Java's naming conventions.