Add scheduled rebalancing

[sisyphusSmiling]

Description

• Adds scheduled rebalancing support with individualized RebalanceHandlers wired into a central per-Pool Registry
• Support for per-Position recurring configuration as an extensible path
• Adds support in FCM Pool for Position ID visibility to ensure non-existent pids are not registered
• Tests passing, but I wasn't able to add tests specific to this new setup

Lifecycle

Creation

1. Position is created
2. Pool registers the PID in its associated Registry in account storage, optionally passing a PID-specific recurring config
3. Registry stores the PID in its registry
4. Registry initializes a RebalanceHandler in storage with paths derived from the Pool UUID & the Position ID
5. Registry schedules the first scheduled rebalance based on either the custom or default recurring config

Updating Default Recurring Config

1. Run the set_default_rebalance_recurring_config.cdc transaction with the desired values
2. Registry stores the updated config as default
3. Any successive RebalanceHandler scheduled executions are scheduled using the default (unless they have a custom config stored)

Steps to Initialize from Current State

1. Update FCM contract
2. Deploy FCMRegistry contract to FMC account (see contract init for starting default config values) - Registry is initialized in account storage
3. Run backfill_positions.cdc transaction (--compute-limit 9999) which will register all existing PIDs in the Registry. This should spin up RebalanceHandlers for all existing Positions

• If you run into computation limits (possible on Testnet especially)
  1. Get all Position IDs (see get_position_ids.cdc script)
  2. Pass in segments of the returned ID array in to backfill_specific_positions.cdc transaction to backfill in partitions. Again, the transaction will fail if one of the provided IDs does not exist in the Pool as a failsafe.

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For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the standards mentioned here.
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels
• Go WTF 💚