Evaluate switching the swap API from boltz.exchange to SatsRouting

[MoritzKa]

API documentation: https://github.com/SatsRouting/satsrouting-api-docs

Outline the required changes to assess the required time for the switch.

[rolznz]

The API identifier (e.g. "boltz", "satsrouting") could be returned from getalby.com. CC @bumi

[rolznz]

This is now available in the internal alby info endpoint as swap_provider ("satsrouting' or "boltz") in the hub object next to latest_version and latest_release_notes. If another value is set that we don't support, then swaps should be disabled.