Add monero namespace

[silverpill]

#41

[bumblefudge]

This is great, @silverpill , glad to see this moving forward! Sorry for the delay, I am on family leave and have been off github. As soon as any other editor approves, we'll merge this.

[silverpill]

@bumblefudge I've reviewed your edits; no objections.

One thing I'm still uncertain about is the length of chain ID. Since there's only a small number of Monero chains, the genesis block hash can be truncated to a fewer characters, for example:

# Monero mainnet (32 chars, current proposal)
monero:418015bb9ae982a1975da7d79277c270

# Monero mainnet (6 chars, more ergonomic?)
monero:418015

But I'm leaning towards keeping 32 chars.

[bumblefudge]

I think the general trend has been towards shorter, but it really comes down to the ergonomics and tradeoffs of whom you think will be using these URIs outside the native/community tooling for cross-chain purposes. If you think those URIs are more useful shortened, I don't think the loss of entropy is a significant collision risk here-- after all, they're already truncated, so it saves space for longer segments after the :! Let me know either way, because it's ready to merge in either form; that said, if you'd rather poll the dev community or ping a few people working on cross-chain apps, take your time and bump this thread when you've decided!

[silverpill]

I think it can be merged as is. I posted about it in several channels, but so far no one expressed interest in using this standard.
If needed, we can amend the spec later (can we?).