feat(SQO): Implement RPC failover, retry logic and notification on RPC provider rotation.

[MoonBoi9001]

Description:

This PR introduces a more granular RPC failover mechanism, smarter retry logic, real-time Slack notifications for provider rotations, and bug fixes.

Key Changes:

1. Granular RPC Failover and Retry Logic:

• Replaced the previous transaction-level failover with a more granular, stateful mechanism. The client now maintains a connection and rotates to the next RPC provider only when a specific network call fails repeatedly.
• Introduced a central _execute_rpc_call method that wraps web3 calls (e.g., get_block, estimate_gas) with a retry then rotate strategy preventing transaction failures due to network issues.
• The @retry_with_backoff decorator is now more focused, targeting a specifc range of network-related exceptions.

2. Slack Notifications for RPC Rotation:

• Integrated SlackNotifier to send a notification whenever the active RPC provider is changed, offering real-time RPC health monitoring.

3. Other:

• Resolved mypy type-hinting errors.
• Updated README.md and config.toml.example.