Why?

Closes #47
In an enterprise context having an auditable log of SCIM requests is essential

What?

• add option to configure request logging
• log every request if logging is configured

Testing Notes

• works with config.audit_logger unset
• logs request if config.audit_logger is set to a class name string
• logs request if config.audit_logger is set to something that responds to info

Todo

I'm planning to mark this "ready for review" once I add rspec test cases for the changes and fix any lint violations

Alternatives Considered

Since it just calls info with the request object, it isn't particularly useful with actual Logger instances. Maybe requiring some ScimRails specific interface would be better? (Along the lines of the on_error config option)