Configuration pre-install validation against schema

[guidograzioli]

Fix #55

Ideally active_address_settings items should accept a map of arbitrary activemq settings (in snake-case instead of kebab-case); given a specific activemq version, the generated configuration should be validate against the corresponding xsd, possibly in the prereq phase. An additional variable activemq_address_settings_defaults should control the output (or not) of passed-in parameters that are defined as default in the xml schema, in order to explicitly fix a configuration between schema updates, or alternatively accept whatever is the default of that version.

This PR adds extra tasks before the install/configuration phase, which take care of fetching the xsd schemas for required activemq version, pre-generate the configuration, and perform a schema validation step against each of the broker.xml main elements under <core:core>

Additionally, it refactors how address-settings are generated, so that arbitrary configuration is accepted (and validated).

The activemq_address_settings variable has changed type from list(dict) to list(match(str),parameters(dict), like follows:

  - match: activemq.management#
    parameters:
      dead_letter_address: DLQ
      expiry_address: ExpiryQueue
      redelivery_delay: 0
      max_size_bytes: -1
      message_counter_history_day_limit: 10
      address_full_policy: PAGE
      auto_create_queues: true
      auto_create_addresses: true
      auto_create_jms_queues: true
      auto_create_jms_topics: true

[rpelisse]

LGTM