Using exec instead of &&

[SamMousa]

It would be nice to support syntax that uses exec instead of a subshell.

The syntax for usage would be simple:

entrypoint: [
    "wait",
    "--",
    "myApp"
]

That way no shell is needed and signal handling becomes easier for the app since there's no longer a shell in between.

[ufoscout]

Partially duplicate of #27
Let's continue the discussion there.