Make warp route ID nomenclature stable

[jmrossy]

Currently, as new chains are added to a route, the route ID changes. There would be some benefit to IDs that don't change because once they change, Warp UI route whitelists must be updated.

The current nomenclature was chosen because we wanted IDs that satisfy all these requirements:

1. Token symbol-oriented
2. Avoids route ambiguity (e.g. btwn two USDC routes)
3. Derivable from a WarpCore config without the need for user input (e.g. no prompting for an invented label)
4. Generally human readable (i.e. no random hash for a name)

[jmrossy]

The idea of custom labels for IDs (e.g. USDC/renzo) has been proposed but I'm personally skeptical. I'm worried we'll end up with an inconsistent mess of arbitrary names without a good way to map back to what the route really is. Not sure though, might work