Refactored AWS scripts

* Refactored ELB health to rely on fog instead of right_aws as it is more actively maintained
* Fixed ELB metrics to consider AWS access keys set as environment variables
@priestjim if you are absolutely ok with fallback to nil in case of whatever error - add to the end of line 

`# rubocop:disable RescueModifier`

then your PR will be green and i will accept it with pleasure