Enabled authenticators can be configured using configuration file

[jtuttle]

Add an :authenticators attribute to the Conjur::ConjurConfig object. It should default to an empty string and should be validated to ensure it's a comma-separated list of strings starting w/ "authn-".

Update Authentication::InstalledAuthenticators to use read the authenticators attribute from ConjurConfig instead of the CONJUR_AUTHENTICATORS environment variable.

Tests

• update spec / integration tests for Authentication::InstalledAuthenticators

[kvanblarcum]

I am confused by the wording within this story. With Trusted Proxy, the precedence was established to be CONJUR env variable >>> config file >>> old env variable. But the way this story is worded, it appears that the config file will be given a higher precedence. (read the authenticator attribute from conjurconfig instead of the conjur_auth env variable). I think we need to be consistent.

[h-artzi]

CONJUR_AUTHENTICATORS env variable >> config file >> database configuration