add allowLookups option to offlineplayer function

[sovdeeth]

Description

Since offlineplayer lookups by name can block the server while they request the uuid from Mojang, they can be very dangerous to parse as. This adds a optional parameter to prevent lookups in the offlineplayer() function for Paper 1.16.5+

I would like opinions on the validity of the Notch test though, since it would fail if the user doesn't have an internet connection or the auth servers go down. Let me know if it should be removed.

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Target Minecraft Versions: paper 1.16.5+ Requirements: none Related Issues: none