No way for cooking content

[sleeptightAnsiC]

To launch a Client/Server/Game instance, you need to cook content first. Otherwise it will fail to boot (which is expected).

Currently ue4cli does not support a way to explicitly cook content. The alternatives are:

• cooking from Editor: Platforms > [PlatformName] > Cook Content (proper Target/Configuration must be specified)
• cooking from command line by launching UnrealEditor with -run=cook and few more flags
• cooking from command line by launching RunUAT with BuildCookRun -CookAll (not sure it this gonna work)
• packing the whole project with ue4 package as it also cooks the content during the process

Would be nice to support it since cooking is pretty important and can fail so user might want to test it few times.

References:

• https://docs.unrealengine.com/5.3/en-US/cooking-content-in-unreal-engine/
• https://docs.unrealengine.com/5.3/en-US/build-operations-cooking-packaging-deploying-and-running-projects-in-unreal-engine/

[sleeptightAnsiC]

Partially related to #62
I haven't fully explored the solution for this problem but as mentioned in #62 (comment) it's not worth to fix it right now.