Keep two separate stores to accomplish per-profile sharing:
- Local store, where to push updates manually (save/remove/search)
- Remote iCloud store, where to pull updates from
A profile can be added/removed to/from the iCloud store so that other
devices can push/pull updates to it.
Consequently, updates to the iCloud store will NEVER cause a profile
deletion. Once removed, the profile will stay locally.
Fixes#586Fixes#555