feat(node): place all gwyneth logic in the GwynethNode within Exex

[CeciliaZ030]

• GwynethNode compiled with custom GwynethPayloadBuilder
• build L2 block with default_gwyneth_payload_builder mostly copy from ethereum builder (clean diff)
• initiate a GwynethFullNode in Exex, remove all test context from bin/reth/src/main.rs
• add l1_provider: Option<SyncProvider>, to Gwyneth's payload builder attributes so that we have access to L1 state

By far, one crucial trait has been modified to allow synchronous state access:

/// The types that are used by the engine API.
pub trait PayloadTypes: Send + Sync + Unpin + core::fmt::Debug + Clone {
    /// The built payload type.
    type BuiltPayload: BuiltPayload + Clone + Unpin;

    /// The RPC payload attributes type the CL node emits via the engine API.
    type PayloadAttributes: PayloadAttributes + Unpin;

    /// The payload attributes type that contains information about a running payload job.
    type PayloadBuilderAttributes: PayloadBuilderAttributes<RpcPayloadAttributes = Self::PayloadAttributes>
        + Clone
        + Unpin;

    #[cfg(feature = "gwyneth")]
    /// Access L1 read-only state provider, in particular Arc<Box<dyn StateProvider>>
    type SyncProvider;
}

For this reason we add a "gwyneth" flag to all downstream dependency.