Implement a converter that bridges the old MEA topics to the new ones.

[didier-wenzek]

As we plan a major refactoring of all the MQTT topics used by thin-edge, we have to provide some backward compatibilities. During a transition period, thin-edge will support the old as well as the new schemes, using a converter that re-publishes any measurement, event or alarm received on a tedge/# topic to the appropriate new te/# topic.

• All the messages must be re-published unchanged - same content, QoS and retain flag, from the old to the new topic.
• There is only one exception for the severity of the alarms (that has to be extracted from the tedge topic and pushed into the json payload of the message).
• The complete specifications of this conversion are here.
• The simpler is to use a Converter and to launch this actor inside the tedge-agent.

[PradeepKiruvale]

The table below shows mapping the tedge topic to the te topic and if there are any changes needed.

tedge topic	te topic	other updates
tedge/measurements	te/device/main///m/
tedge/measurements/child	te/device/child///m/
tedge/alarms/severity/alarm_type	te/device/main///a/alarm_type	add severity into payload
tedge/alarms/severity/child/alarm_type	te/device/child///a/alarm_type	add severity into payload
tedge/events/event_type	te/device/main///e/event_type
tedge/events/child/event_type	te/device/child///e/event_type
tedge/commands/res/software/list	te/device/main/cmd/software_list/<cmd_id>
tedge/commands/res/software/update	te/device/main/cmd/software_update/<cmd_id>
tedge/+/commands/res/config_snapshot	te/device/main/cmd/config_snapshot/<cmd_id>
tedge/+/commands/res/config_snapshot	te/device/child/cmd/config_snapshot/<cmd_id>
tedge/+/commands/res/config_update	te/device/main/cmd/config_update/<cmd_id>
tedge/+/commands/res/config_update	te/device/child/cmd/config_update/<cmd_id>
tedge/+/commands/res/firmware_update	te/device/main/cmd/firmware_update/<cmd_id>
tedge/+/commands/res/firmware_update	te/device/child/cmd/firmware_update/<cmd_id>
tedge/commands/res/control/restart	te/device/main/cmd/restart/<cmd_id>
tedge/health/servcie-name	te/device/+/service/tedge-agent/status/health

[gligorisaev]

@PradeepKiruvale the test case that is part of your PR is not verifiing the first point of Didier description:
'All the messages must be re-published unchanged - same content, QoS and retain flag, from the old to the new topic.'

[gligorisaev]

QA has thoroughly checked the feature and here are the results:

• Test for ticket exists in the test suite.
  /tests/RobotFramework/tests/tedge_to_te_converter/convert_tedge_topics_to_te_topics.robot
• QA has tested the feature and it meets the required specifications.