First

• merge https://github.com/massalabs/massa-web3/blob/c87fa592dd86a30099e061c9c1aacb7a4a5fba50/packages/massa-web3/open_rpc/massa.api.json (public api part is up to date)

And then we should also :

• Update massa Amount serializer/deserializer str to accept string in nMAS and u64 nMAS (check if is decimal or no)
• update the openrpc api spec and create Amount wrapper which is oneOf [ string, number]