etlas project --watch-files

[rahulmutt]

We should make an etlas project command that lets you query with precision about all the details of your project (dependencies, info specified in cabal file, etc) and in particular, we want something that spits out all the monitored files used internally by the new-build mechanism. This allows, for example, Gradle/Bazel to know exactly what files a particular build depends on and allows them to trigger etlas when something changes.