Environment variable to control the default output style

[jonathanmorley]

I prefer using --output-style=stream locally, so that i can see and track the output of targets (and dependencies).

I would like to be able to make this a system-wide preference, rather than needing to add it when invoking commands.

I would imagine something like NX_DEFAULT_OUTPUT_STYLE in terms of naming.

[flo-sch]

This would also be handy in CI environments, where it could be controlled from a single variable instead of having to specify --output-style=static to each command manually