merge upstream PRs

[chrisguida]

• bkpr: add two custom notifications that we listen for ElementsProject/lightning#7258
• bitcoindevkit/bdk@master...ValuedMammal:bdk:example/scanblocks
• add simple_http_with_timeout apoelstra/rust-jsonrpc#109
• add scanblocks call rust-bitcoin/rust-bitcoincore-rpc#317
• wip try to implement scanblocks rpc to speed up full wallet scans vladimirfomene/bdk#2