Ensure same build result for debug and release builds

[Fatme]

Is your feature request related to a problem? Please describe.
Currently when --env.snapshot is passed for debug builds, NativeScript CLI shows an warning and starts webpack compilation without --env.snapshot option. This led to the problem that different build result is produced when application is built in release and debug mode.

Describe the solution you'd like
We need a common, unified way so the application can produce the same build result regardless of the build mode (release or debug)