Add KakarotTransactions trait to upstream send_raw_transaction

[tcoratger]

Context:

As a follow-up to #1321, this pull request addresses the circular dependency between the mempool and the provider.

Changes Introduced:

1. Creation of KakarotTransactions Trait:

   • The send_raw_transaction method has been moved to a new trait called KakarotTransactions.
   • This trait is implemented for our EthClient.
   • This design is inspired by the FullEthApi trait in the reth project, where the trait is implemented for EthApi, which itself contains both a provider and a pool.

2. Separation of Implementations:

   • By upstreaming the send_raw_transaction method, we start to differentiate between the Client's implementations and those of the provider.
   • The provider, being lower in the hierarchy, serves the client. This refactor makes it clear that the pool only needs access to the provider, not the entire client.

3. Elimination of Circular Dependency:

   • The previous circular dependency between the pool and the provider is removed. Now, the pool relies solely on the provider, not the full client.

[eugypalu]

LGTM