- Use the new `status` argument for `delinvoice`, remove our manual status verification.
- Use the new `paid_at` field instead of using our local time when processing payments,
rename our `completed_at` to match (but still expose `completed_at` for now).
- Read from the `expires_at` field (renamed from `expiry_time`, now matches our local field name).
- test: `getpeers` -> `listpeers`
- test: Remove use of addfunds.
- test: Set --allow-deprecated-apis=false by default, overridable with ALLOW_DEPRECATED.
- Remove the `completed` column and determine completion status based on the presence of `pay_index`,
but still expose `completed` for now.
Not entirely related to c-lightning's API changes, but tightly coupled with the other changes.
Refs: https://github.com/ElementsProject/lightning/pull/623