feat: Lightning Payment Verification

[SeverinAlexB]

Adds Lightning Payment Verifications to Homegate. It provides 3 endpoints:

• Create verification -> Provides a Bolt11 invoice
• Get verification -> Provides the state of the verification.
• Await verification -> Long poll endpoint that completes when the payment arrives.

I am not sure how/if I can test anything that involves phoenixd. It would require a lot of mocking which I am not sure is worth it. At the moment, the flow is mostly tested manually.

[86667]

I have the syncer logic to go over still, here's the first few suggestions

[86667]

Syncer looks good 👍

[86667]

Couple points about API responses:

• We return id but document input param as payment_hash
• We have a mix of camel case and snake case- Ln response types are converted to camel case at serialisation.