feat: v0.8.0: bump alloy, update API types

[merklefruit]

This PR bumps the package version from v0.7.4 to v0.8.0.

Here is a list of all the changes:

• updated old dependencies: mainly alloy and ethereum_ssz
• got rid of reth_primitives as dependency as now all the types we need are upstreamed into alloy
• added all background task handles to the Client struct so that we have a way to manually kill them if necessary
• added a Client::kill_all_background_tasks() function to kill all outstanding streams
• updated all send_ API functions to return tx_hashes as alloy::primitives::B256 instead of String.
• removed all unused dependencies (and added clippy lint rule for the future).
• added usage of thiserror for library error enum

Some types have changed due to how outdated alloy was. In particular:

• sending typed transactions now expects alloy::consensus::TxEnvelope
• subscribing to transactions returns a stream of alloy::consensus::transaction::Recovered<TxEnvelope>
• subscribing to blob txs returns Recovered<alloy::consensus::Signed<TxEip4844WithSidecar>>
• subscribing to execution payloads returns a stream of alloy::consensus::Block<TxEnvelope>>

Given the type changes to the public API, this marks a breaking change.