Acm cert and user messaging improvements with config

[tongueroo]

acm_cert helper improvements: warn when not found and only create ssl listener if cert is found

messaging improvements: provide exact line of context of the config with the issue

• update dsl_evaluator dependency to at least 0.3.0

improve squeezer: prevent infinite loop for edge case when data is [nil]

• could happen before when config.elb.ssl.certificates = nil
• ListenerSsl#certificates -> normalize which then produces [nil]
• the squeezer would go into an infinite loop with this super edge case
• added additional safeguards by checking for ssl.certificates for nil
• and certs.flatten.compact and create_listener_ssl? check
• also add spec