crypto: Improve control of FIPS mode

Default to FIPS off even in FIPS builds.
Add JS API to check and control FIPS mode.
Add command line arguments to force FIPS on/off.
Respect OPENSSL_CONF variable and read the config.
Add testing for new features.

Fixes: https://github.com/nodejs/node/issues/3819
PR-URL: https://github.com/nodejs/node/pull/5181


Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-by: Michael Dawson <michael_dawson@ca.ibm.com>