Merge pull request #1505 from tnull/2022-05-support-0conf-channeltype

Support `ZeroConf` channel type.

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

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

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

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