Feat: RPCresponse validation flag & tests, also included some in-code documentation

[ricardocr987]

Used the same library as solana web3 library (superstruct), but changed the method they use create (for example: https://github.com/solana-labs/solana-web3.js/blob/master/src/connection.ts#L4094) for assert, because they apart of validate the response, they process it, to change some strings to publickey directly during the validation (which we dont want to).

[MHHukiewitz]

LGTM

It's a little bit mixed in what has been done in the PR, but as all these changes won't influence current production code, as far as I can see, it should be ok.