Allow using asconfig.json instead of project.apm

[Fancy2209]

asconfig.json is the default file used for projects in VSCode with the AS3 Extension, it would be neat if apm could handle using that as a project file instead of having a asconfig.json AND a project.apm on my projects.

[marchbold]

Going to convert this to a discussion, as I think this needs to be talked through before implementing.