Create a proto encoded TxBody with a MsgSend

[webmaster128]

At https://github.com/cosmos/cosmos-sdk/blob/master/x/bank/types/types.proto there is a protobuf definition for MsgSend. We need a demo package (just tests, no API design) that

• Takes as JS object plus a MsgSend protobuf schema and turns it into a serialized binary
• This binary needs to be embedded in a google.protobuf.Any
• Creates a TxBody protobuf document using the schema from https://github.com/cosmos/cosmos-sdk/blob/master/types/tx/types.proto and serialized it

This requires looking into possible protobuf encoding libraries.

The spec for that is ADR-020 and there is an overview available at https://warta.it/blog/cosmos-sdk-protobuf-signing