Token pool definitions are all broadcast on a single topic

[awrichar]

Within a namespace, all token pool definition messages are broadcast on one topic. They could be split onto unique topics to enhance throughput, as long as the topic gives a deterministic "winner" for creating the pool in the case of a race (ie the topic should probably be some function of namespace+name).

[peterbroadhurst]

For identities we use the did because that:

• Includes the name
• Includes something unique to identities (did:)

firefly/pkg/fftypes/identity.go

Lines 152 to 156 in 491c272

	func (i *IdentityBase) Topic() string {
	h := sha256.New()
	h.Write([]byte(i.DID))
	return HashResult(h).String()
	}

I think for token pools, we'd need to hash:

• A string such as tokenpool
• The name

[awrichar]

Fixed in #600