Store all company information in our database not in Intercom

[rgoj]

Once we do #613, it'd be nice to also remove our reliance on storing information in Intercom! This will likely also be useful / necessary for allowing users to set up multiple organisations (#611).

Also see notes from Tom's requirements doc:

Addressing this will also require reworking how we use Intercom for user/organisation data since at the moment a free trial is associated with a person, not an organisation, and setting up a new org would need to trigger a new free trial.

This could be a moment to consider whether we want to be wedded to Intercom forever. Could be a chance to move - it’s quite costly especially as we grow and not very user friendly.

[rgoj]

An interesting case of this being a problem occurred yesterday: https://maptio.slack.com/archives/C49MA8T3Q/p1657549845286009?thread_ts=1657532571.312329&cid=C49MA8T3Q