feat: BlockchainDbMeta builder

[yash-atreya]

Motivation

Ref #21

Solution

Adds builder methods to instantiate BlockchainDbMeta

 let block =
        provider.get_block(BlockId::latest(), BlockTransactionsKind::Hashes).await?.unwrap();

 let meta = BlockchainDbMeta::default()
        .with_chain_id(31337)
        .with_block(block.inner)
        .with_url(anvil.endpoint());

PR Checklist

• Added Tests
• Added Documentation
• Breaking changes

[yash-atreya]

This is not breaking, keeping the BlockchainDbMeta::new() method as is.

[mattsse]

type nits