Merge pull request #2492 from optout21/payment-hash-display

[minor] Add Display to Payment ID types

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/ln/outbound_payment.rs
Simple merge