Add liveries from new aircrafts from the MegaPack

[taz8707]

Description

I am missing the aircrafts you can download from the Project Mega Pack on Discord, like the Airbus 321 and 330.
Currently, you have to download an additional zip file with the extra liveries.

Solution

It would be very nice to have the liverie packs of these additional aircrafts in the Livery Manager.

Why is this the best solution?

So any updated or added liveries of these aircrafts are added through one (and the best) livery manager.

Additional context

no additional context :-)