Get the in-game ping + allow checking other player's

Also adds relevant permissions for checking other players

Uses reflection to get the CraftPlayer for the given Player object, call it's getHandle method and then get the ping field from that class. Should work over any Minecraft version with the same structure + class naming (A LOT). Avoids using import for NMS classes to avoid version lock.

Removes all dependencies on the underlying OS from using InetAddress reachable.

Fixes https://github.com/Elllzman619/PingChecker/issues/1