Add Oxide.Ext.Discord.dll

[JoseManuelPedraja]

I have added in my serverin case it can be useful to you in the future for those of us who use discord verification.

this utils/get-or-update-plugins.sh

if [ ! -f 'serverfiles/RustDedicated_Data/Managed/Oxide.Ext.Discord.dll' ]; then
  curl -fLo serverfiles/RustDedicated_Data/Managed/Oxide.Ext.Discord.dll \
    https://umod.org/extensions/discord/latest/Oxide.Ext.Discord.dll
fi

[samrocketman]

Would it make sense for me to add support for arbitrary DLL downloads like this?

[JoseManuelPedraja]

If your server uses the Discord or Whitelist kits,

And it makes it easier for anyone using it to install. It was just another utility.