Adds feature from Boto missing in ec2_lc module

This PR adds the feature present in Boto and missing in Ansible ec2_lc:

- kernel_id for custom kernel
- ramdisk_id for custom ramdisk
- instance_profile_name to launch instances within an IAM role
- ebs_optimized (to launch an EBS optimized instance or not)
- associate_public_ip_address to associate a public IP address within a VPC
- instance_monitoring to enable Cloudwatch on the instance (replaces https://github.com/ansible/ansible/pull/7896)