Add IPak projects and building

[Laupetin]

Prototype for IPak building.

To be able to build other things than fastfiles this also introduces the possibility to specify the type of output, which can now either be fastfile or ipak.

IPaks are built from a project definition file (.zone), however only images are taken.
It is also possible to specify an assetlist inside this project definition file to load an assetlist which might be a better way for the future to build IPaks since it requires all images to be specified inside its source.

This is due to being different to fastfile building which loads all asset dependencies as well so any images that are a dependency of a specified asset would be loaded as well. This is NOT the case for IPaks.

So in the future it might be a good idea to implement assetfile generation after linking for Linker.

Also usability for IPaks can further be improved if it was possible to specify another project to build inside a project file.
Like a subproject of some sort.
This is due to the structure of the projects being something like zone_raw/project/zone_source/fastfile_source.zone.
Currently having the appropriate ipak source in zone_raw/project/zone_source/ipak_source.zone is not possible.

Would probably be good as well to additionally add documentation about how IPaks are structured and add integration tests for writing and loading IPaks.