Unlike "sendonionmessage" which instructs us to send to a peer, this
process it locally (presumably, it contains the next hop). This is
useful because it allows us to process an onion message which starts
with us (a legal case for a blinded path supplied by someone else!).
It also opens the door to bolt12 self-pay.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I removed these prematurely: we *haven't* had a release since
introducing them!
This consists of reverting d15d629b8b
"plugins/fetchinvoice: remove obsolete string-based API." and
plugins/fetchinvoice: remove obsolete string-based
API. "onion_messages: remove obs2 support."
Some minor changes due to updated fromwire_tlv API since they
were removed, but not much.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-EXPERIMENTAL: REVERT: Removed backwards compat with onion messages from v0.10.1.
