feat(starknet_l1_provider): add Starknet contract

Use alloy to generate a `Starknet` instance, which can interact with
contract on L1.
Using `Starknet::new` assumes the contract _has already been deployed_
at the given address, and will delegate calls to that address.

Note: since errors are not possible during construction, the error
handling was removed.

crates/papyrus_base_layer/Cargo.toml

@@ -17,7 +17,7 @@ alloy-dyn-abi.workspace = true
 alloy-json-rpc.workspace = true
 alloy-primitives.workspace = true
 alloy-provider.workspace = true
-alloy-sol-types.workspace = true
+alloy-sol-types = { workspace = true, features = ["json"] }
 alloy-transport.workspace = true
 alloy-transport-http.workspace = true
 async-trait.workspace = true