Allow for import of contacts #59
Description
One should be able to import (and export) contact lists from the repeater, like one does with a companion.
As a user, I would want to be able to export my contacts list from my companion, and upload in the console my Meshcore export json file, and then add / merge with the existing contacts.
Similarly, I should be able to export my contacts and data from the console, so I could move them to another repeater if I move installations, etc.