Merge pull request #1867 from wpaulino/remove-signer-persistence

Re-derive signers instead of persisting them

diff --cc fuzz/src/chanmon_consistency.rs
Simple merge

diff --cc fuzz/src/full_stack.rs
Simple merge

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

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

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

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

diff --cc lightning/src/ln/chanmon_update_fail_tests.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/functional_tests.rs
Simple merge

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