Store and report dock pose

[andchiind]

Describe the improvement you would like to see
Currently ISAR is aware of the installation it is at, and its pose within a specific region of this installation, but it is not aware of the location of its home/dock within this region. I suggest that to make ISAR completely responsible for maintaining localisation and docking, that this position also be stored in ISAR. We can then send this information in the MQTT event so that Flotilla becomes aware of it without needing to set it themselves.

How will this change existing functionality?
It will make ISAR more independent regarding systems we want it to manage, in this case docking/localisation.

This Flotilla issue is dependent on this ISAR issue: equinor/flotilla#1876

How will this improvement affect the current Threat Model?
N/A