Custom RPC methods for DummyOrdered pallet (#317)

* RPC for DummyOrdered

* add test for RPC

* proof returned by RPC is Vec<<Vec<u8>>>.encode()

* retrieval -> receiving

* bp-runtime crate

* bp-runtime supports no_std

* cargo fmt --all

* jsonrpc_core::BoxFuture

* Update modules/message-lane/rpc/Cargo.toml

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* messageLane_ prefix for RPC methods

* Update primitives/runtime/Cargo.toml

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update primitives/runtime/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

* Update modules/message-lane/rpc/src/lib.rs

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>

Co-authored-by: Hernando Castano <HCastano@users.noreply.github.com>