Availability Recovery: subsystem skeleton

## Issue summary

Create a skeleton code for the implementation of the Availability Recovery subsystem, which is described in the Design proposal for the Availability Recovery subsystem.

Implement next types:
- [ ] Create a new package called `availabilityrecovery`
- [ ] Create AvailbilityRecoverySubsystem struct
- [ ] RecoveryStrategy interface
- [ ] RecoveryParams
- [ ] RecoverySubsystemState and RecoveryHandle
- [ ] Implement messaging with Overseer
- [ ] Import interfaces for network request/response
- [ ] Prepare necessary infrastructure to call AvailabilityStoreMessage::QueryAvailableData and QueryChunkSize
- [ ] Process ActiveLeaves message

## Other information and links
- https://paritytech.github.io/polkadot-sdk/book/node/availability/availability-recovery.html
Look at other skeleton PRs to get an idea of what to code and what will become and TODO and a new issue
- https://github.com/ChainSafe/gossamer/pull/3497
- https://github.com/ChainSafe/gossamer/pull/3521
- https://github.com/ChainSafe/gossamer/pull/3512