Merge pull request #2400 from TheBlueMatt/2023-07-kill-vec_type

Fix backwards compat for blocked_monitor_updates and finally kill `vec_type`

diff --cc lightning/src/chain/channelmonitor.rs
Simple merge

diff --cc lightning/src/ln/channel.rs
Simple merge

diff --cc lightning/src/ln/channelmanager.rs
Simple merge

diff --cc lightning/src/routing/gossip.rs
Simple merge

diff --cc lightning/src/routing/router.rs
Simple merge

diff --cc lightning/src/util/ser_macros.rs
Simple merge