Feature/amqps protocol

[StWiemann]

Since we are going to use AMQP in a future project I changed the URI-generation a bit to enable TLS-connections. It does not yet support client-certificates, since that isn't strictly needed in my use-case but I thought maybe somebody else might be interested in AMQPS.

I did it analogous to mqtts, even though that might confuse some people due to AMQP-Protocols 0.9.1 vs 1.0 being a very different thing. This still uses 0.9.1, nothing changed there.

The new Env would be: - IOTA_AMQP_PROTOCOL=amqp or amqps

Don't really know if the testing-part works as intended. Basically just c/p'ed from MQTT_PROTOCOL...

[mapedraza]

Thank you for your contribution @StWiemann

An entry to CHANGES_NEXT_RELEASE file is required before merging.

Could you please open a twin PR on https://github.com/telefonicaid/iotagent-ul repo?

[fgalan]

Thank you for your contribution @StWiemann

An entry to CHANGES_NEXT_RELEASE file is required before merging.

Could you please open a twin PR on https://github.com/telefonicaid/iotagent-ul repo?

@StWiemann did you take into account this feedback provided by @mapedraza , please? Thanks!