Collections v0.2 - assets, ownership change, processing flow

[tzarebczan]

• Add asset ids to collection (related: Collections registry - use SQLite  #15).
• Support sorting of asset ids inside a collection and registry side too (maybe not needed on reg?)
• Support ownership change. Keep Creator so we know who originally created it if we need to, but also support returning/showing of Owner (just use process owner or a new field?)

Processing Flow

• Profile process should be responsible for spawning a collection process - profile process should have a handler to do this (one less message to create a collection)
• Collection should be responsible for adding itself to the registry (done via client today. Use message between collection and collection registry.
• Updates to collections should flow from the profile (similar to how we update assets) - both for metadata + adding/removing/editing