Split converted data into multiple modpacks

At the moment, the converter will export all generated and converted data from a game into a single modpack. However, there would be benefits for splitting data into multiple modpacks in the following situations:

• Separating DLCs/expansions from the main game (one modpack per expansion)
• Having separate modpacks for game data, media and translations

The former is useful when a game has optional DLCs. We cannot expect everyone to have all available DLCs, hence converting into a single modpack will not always yield the same result. Separating every expansion into its own modpack should solve that problem.

In the latter case, modpack splitting helps by separating translation data, which is often only the regional language for the original game releases, from the universal game data containing unit stats. Not splitting the modpacks result in different modpacks for different regional releases.

To do this, there should be a way to assign a modpack to a generated nyan object during conversion. If an object O is part of a set member value in modpack A, but assigned to modpack B, then a patch should be generated so that B patches O into A.

Start by tracing the converter's generated nyan objects and how set-member values select a modpack. Define and test assignment and cross-modpack patch behavior for DLC, media, and translation splits; done means one conversion can emit multiple modpacks with the described patch relationship.