TS Allocator / ArcHost refactor

[mariakleiner]

(includes https://github.com/PolymerLabs/arcs/pull/7024)

• Use ArcInfo (instead of Arc) where possible
• spin up inner arcs via allocator
• use ArcInfo everywhere (almost) in strategizing and planning
• PlanPartition include particles and handles (instead of a Recipe)
• implement cloneForSpeculativeExecution via allocator

[shans]

Can you describe the places where you don't use ArcInfo in strategizing and planning (and why)?

[mariakleiner]

Can you describe the places where you don't use ArcInfo in strategizing and planning (and why)?

There are 2 places:

• Speculator: where we create a speculative arc and instantiate the recipe for realz
• Planificator: where we (1) use the storageKey in the Arc to create stores for suggestions and search - this is straightforward to refactor and get rid of, but (2) subscribe to changes in the Arc's stores to trigger replanning - this needs a live arc (or just a storage-service with some additional refactoring)