Messages: replace safeAppId with origin

[katspaugh]

What is needed?

The message proposal endpoint atm takes a safeAppId as a way to identify from where the message comes. This has a few issues:

• It's not consistent with tx proposals which take an origin string (the URL of a dapp)
• If you delete the matching Safe App, this ID cannot be recreated, so all the messages are orphaned
• It doesn't convey any useful information for non-Safe App messages, i.e. for all WalletConnect-connected dapps
• Transaction service knows nothing about Safe Apps, so it's not applicable to non-wallet ecosystem participants

Hence I suggest to replace safeAppId with an arbitrary URL (we can call it also origin), so that we can show something useful to the user in the history.

E.g. user connects to OpenSea and signs a message. We send a POST proposal with "origin": "https://opensea.io/". Message history returns https://opensea.io in the name field of the Message list item.

Endpoint

Timeline

Q3 or later