os: implement os.type() using uv_os_uname()

The happy path behavior should be identical on all
platforms except MinGW, which now identifies MinGW
separately from Windows.

PR-URL: https://github.com/nodejs/node/pull/25659


Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>