Profile/CloudAPI top-level CLI options are now applied to the current
profile. Also clean up loading of the 'env' profile a bit so that
special casing of that is more hidden in "config.js".
Also add support for the TRITON_URL, TRITON_TLS_INSECURE and
TRITON_ACCOUNT envvars. (I didn't add TRITON_KEY_ID because a coming
change will do better than that.)
Fixes#28, #24.