restructure/refactor to be more modular and more easily consumable

• restructure units into modules (asg, rds, nlb)
• remove the amount of redundant inputs into a list of maps for servers/agents
• add capability for auto deploying manifests via write_files in cloudinit
• simplify api into k3s cli by simply providing a k3s-exec variable to handle most of the arguments
• convert to RHEL8.1 as the base AMI tested
• turn selinux into Permissive by default until further testing has been done
• add a pre-commit hook to run terraform fmt --recursive (more to come)
• be a lot more dry...