Publish status and mission spec to MQTT broker

[aeshub]

Describe the new feature you would like to see
ISAR should support publishing the status of the current task and the mission schedule as a whole to an external broker. This is an integration with equinor/flotilla#47 and is required for ISAR to connect with Flotilla.

Describe the solution you'd like
Using a client library for python to communicate with the broker (for example https://pypi.org/project/paho-mqtt/) the status of the current task should be published whenever there is a change. The publishing should be such that the topic remembers the last known value.

The same should be done for the mission object which contains all tasks in the mission and a summary of their final and current statuses.

How will this feature affect the current Threat Model?
ISAR will be required to authenticate to the MQTT broker. Exactly how will depend on the implementation of equinor/flotilla#47.

• Note that this will mean a data flow out of the application which will be picked up by the broker and further on picked up by databases/fleet management.

[aeshub]

Awaiting resolution of equinor/flotilla#47