V2: Use monero-wallet-rpc and public node

[xmrsale]

since we have had trouble building a view-only mode with blockexplorers that maintains good UX. We have pursued removing the dependency of running a node for xmrSale.

Here we download the latest wallet cli and rpc from getmonero.org, and use them to

• Initialize a wallet with a passphrase (USERS MUST BACK THIS UP)
• Sync wallet with monero blockchain using a public node (currently moneroworld.com)
• Host monero-wallet-rpc in background for xmrSale to call new addresses and confirm payments

IMO the configuration step could be smoother. But this is a massive improvement from the previous requirements from the user, having them configure their node and rpc services themselves.

[xmrsale]

https://github.com/xmrsale/xmrSale/pull/5 up to dated pull request