Rename to walletauth-template?

[bmann]

I get confused just looking at the ODD repos trying to figure out the difference between odd-walletauth and this walletauth repo.

I think this should be walletauth-template -- a template for making walletauth-powered ODD apps -- and the other one is the SDK / library.

Tweaks to READMEs of both, I also have #19 filed here, which should really be in the other repo. Where we explain "next steps for WalletAuth", which is basically "this can work on native mobile, we wait for 5630 before it works widely".