Insecure TLS in RabbitMQ Collector

[mjtice]

Looking at the source code I can specify the scheme for the RabbitMQ Collector. Unfortunately, because we use self-signed certs, this is failing with errors like

URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:579)>
Would you guys be open to a PR to allow a config option that will let the user skip cert verification?

[shortdudey123]

Go ahead and submit a PR.