Sync organizations to linked address book contact

[LGro]

Organizations are currently available in Coagulate for sharing but are not synced to linked address book contacts. This is because the flutter_contacts data model does not support a label or ID for organization entries, so it seems impossible to track which ones are managed by Coagulate like we do with the other labelled ones.

One proposal to still allow organization info sync to linked address book contacts is to ask users to opt in or out of Coagulate taking over all organizations of that contact. That would effectively prevent users from manually managing some organizations while others are managed by Coagulate. This is inconsistent with the other detail categories but unless we move to a more drastic "this whole contact is managed by coagulate" with any user changes being overwritten - potentially requiring the option for users to manually add contact details in Coagulate that are then set to the address book.