Webhooks spec missing event schema

[brad-dow]

In reviewing the webhooks spec, I noticed that it was missing the following:

• Missing incomingPaymentCreated event
• Missing amount schema defined (several properties reference it)

[mkurapov]

@brad-dow

Missing amount schema defined (several properties reference it)

The schema isn't missing the amount field per se, it's linked from the shared Open Payments resource server schema which we pull in programmatically from the open-payments package. It could easily be standalone though, we just need to write out the full amount schema (not too bad).

Just a note: for this webhook spec, it's easy to remove the dependency on the OP resource server spec, but will be a different story for the IDP spec since we import a lot more from the OP auth server spec.

[mkurapov]

@oana-lolea maybe for now, we can just add the amount schema in the spec directly (without referencing the other spec). Since its just one object with three fields that I don't suppose would change, I'm not worried about diverging from the Open Payments specs.

This also means we can remove the copy-op-schemas (and postinstall scripts in backend).