add some permissions to the execution policy

[cchristous]

This adds a few new permissions to the execution policy. These permissions are not overly critical.

• The delete permissions I ended up needing when failing to update stacks and rolling back.
• The autoscaling:CreateOrUpdateTags was needed for tagging ASGs.
• The removal of the LaunchTemplateAccess block was necessary because the policy hit the character limit when adding the other permissions. Conveniently, the permissions in the LaunchTemplateAccess block were replicated earlier in the policy: https://github.com/renderedtext/agent-aws-stack/blob/master/execution-policy.json#L18-L25.

[lucaspin]

/sem-approve