feature request: Associate a string with an asset, without restarting elementds

Our use case is that we are creating certificates of ownership/authenticity for media, that can be purchased and resold. The assets are identified by a signed hash of the media. Thus the signficant "identifier" of the certificate is the signed hash, not the guid constructed by Elements in the issuance. This could be achieved as an asset "name", but we cannot restart elementsd each time a certificate is created.

Best result would be for any node to be able to look up transactions and utxo associated with the string. (Relating to use case: Given the media alone, which contains this signed hash identifier and is thus verifiable, we would like people to be able identify transactions involving it on the blockchain (e.g., who is the rightful owner), without relying on our company's database.)

Acceptable result is for any node to look at some transaction involving the asset (perhaps just the first/issuance?) and see the string.

Fallback is to use data output type, with people crawling the blockchain to find owner.

No files, tests, or entry points are named. Start by tracing asset issuance and the transaction/UTXO lookup paths relevant to asset identifiers, then compare the requested string association with the data-output fallback. Done means a node can associate the string without restarting elementsd and use it to find related transactions or UTXOs.

Written by the indexing model from the issue text.