Async stuff optimization

[basfroman]

• improve determine_block_hash usage (we need to call it before asyncio.gather or before substrate calls)
• apply asyncio.gather where this can improve performance

[SmartDever02]

is someone working on this or can I create a pr? @basfroman

[basfroman]

is someone working on this or can I create a pr? @basfroman

This task is already in development locally.
With all that said, let me express my gratitude for your willingness to help develop the SDK!