Inject config via constructor

Since it is used by every method on Destroyer

Signed-off-by: Abhijit Hiremagalur <abhi@pivotallabs.com>
moved destroying ec2 instances into destroyer class
moved destroying ebs volumes into destroyer class
extracted RdsDestroyer from aws destroy action
moved destroying s3 buckets into destroyer class
extracted VpcDestroyer from aws destroy action
moved destroying key pairs into destroyer class
moved destroying elastic ips into destroyer class
moved destroying security groups into destroyer class
moved destroying route53 records into destroyer class
removed delete_server_certificates since ELB class takes care of serv certs
removed unused delete_vpc method