Add a util for polling transactions after rpc.sendTransaction

[kalepail]

Is your feature request related to a problem? Please describe.
When you successfully submit a transaction via RPC you then have to poll against the getTransaction until it returns something. Everyone is running their own version of this polling function.

Describe the solution you'd like
It would be nice to provide something workable out of the box. Likely just exposing what the AssembleTransaction stuff is already doing. Just need to allow it outside the context of a TS binding library.

Describe alternatives you've considered
Write it myself by hand for every dapp. Ew.

[Shaptic]

Ugh fiiiiiine. PTAL: #1092