[Feature Request] vanity dids

[bddap]

I would like to control a short human readable did like did:dock:bddap. I'm sure others would enjoy similar.

[bddap]

One way to implement this which wouldn't require any on-chain changes would be to hash the human friendly version of the did before looking it up. This can be backwards compatible with the hex and base 58 forms we currently use.

Best to reject special characters like punctuation during lookup to enable future changes.