Provide AMQP broker-connections configuration

[guidograzioli]

Element broker-connections can now be configured with the variable:

Variable	Description	Default
activemq_broker_connections	AMQP broker connections configuration List of { name(str),uri(str),operations(list of dicts) } with operation type in [mirror,sender,receiver,peer]	[]

Sample of mirroring operation:

activemq_broker_connections:
  - uri: 'tcp://<hostname>:<port>'
    name: DC2
    sync: true
    operations:
      - type: mirror
        parameters:
          queue-removal: false

Sample for sender-receiver operation:

activemq_broker_connections:
  - uri: 'tcp://<hostname>:<port>'
    name: other-server
    operations:
      - type: sender
        parameters:
          address-match: 'queues.#'
      - type: receiver
        parameters:
          address-match: 'remotequeues.#'

Broker connections are AMQP connections which allow to configure cross-site fault-tolerance.
For more details, read the artemis documentation and the Configuring AMQ Broker guide

Fix #69