Generate assetlists after linking with Linker

[Laupetin]

Assetlists are already usable for ignoring assets inside project definitions as well as loading all assets from an assetlist.

This is particularly useful when you want to build an IPak with all images from a built zone for example.

To enable this workflow Linker should automatically generate assetlists after successfully linking. These assetlists should be placed in an appropriate source directory in a "assetlist" subfolder.

Would probably also good if creating assetlists could be turned off via cli args. It should be enabled by default though for now.