Renamed config/saml2_settings.php config/saml2.php

[tjallingt]

config/saml2_settings.php and config('saml2_settings') feel kinda redundant, renamed everything to just be saml2 instead.

I send it to this branch because this feels kind of like the "next version" branch and this is a breaking change (although easy to resolve)

[rlcurrall]

This is a kind of old pull request, but would this not break the IdP configurations?

Just poking around in tinker, if I rename the file saml2.php then try to access a configuration for a given IdP which would be in the file /config/saml2/test_idp_settings.php using config('saml2.test_idp_settings'); I get null as it is unable to access those files.

On a second pass it looks like it depends on the version of Laravel you are using. I've only tested it on two versions so far. I know that it doesn't work on 5.4 but it does work on 6.2.