In particular, in the regtests, with incoming peers, we can have multiple transports open with the same node simultaneously
(see e.g. lnworker._request_force_close_from_backup).
We now use the first few bytes of peer_pubkey, as that is potentially familiar to users,
and the first few bytes of sha256(id(self)) to mitigate collisions in case the peer_pubkeys collide.
log excerpt:
```
I/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | handshake done for 030f0bf260acdbd3edcad84d7588ec7c5df4711e87e6a23016f989b8d3a4147230@163.172.94.64:9735
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Sending INIT
I/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | handshake done for 03933884aaf1d6b108397e5efe5c86bcf2d8ca8d2f700eda99db9214fc2712b134@34.250.234.192:9735
D/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | Sending INIT
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Received INIT
I/P | lnpeer.Peer.[LNWallet, 02651acf4a-79696c42] | handshake done for 02651acf4a7096091bf42baad19b3643ea318d6979f6dcc16ebaec43d5b0f4baf2@82.119.233.36:19735
D/P | lnpeer.Peer.[LNWallet, 02651acf4a-79696c42] | Sending INIT
D/P | lnpeer.Peer.[LNWallet, 03933884aa-5e5dce45] | Received INIT
I/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | saved remote_update
D/P | lnpeer.Peer.[LNWallet, 030f0bf260-e0b33756] | Received CHANNEL_REESTABLISH
```
Previously for incoming transports, the diagnostic_name (for log messages)
was just "responder" -- not sufficient to distinguish peers.
We now use the pubkey instead.
For outgoing transports it is f"{host}:{port}" (unchanged).
We could just use the pubkey for both uniformly; but it is quite long, and
it is hard to distinguish them at a glance.
Scenario (prior this change):
A task in lnpeer.Peer.taskgroup raises ORIG_EXC, e.g. in htlc_switch.
The taskgroup then cancels all its tasks and then awaits each (in cancel_remaining):
4e64c56042/aiorpcx/curio.py (L217-L221)
In Peer.main_loop, we would want ORIG_EXC to be raised,
but instead LightningPeerConnectionClosed() will be raised as
the Peer._message_loop() task is cancelled, and it is awaited first in cancel_remaining.
We should make sure that if a task is cancelled it will let the CancelledError
propagate out, or at least it does not raise a different exception instead.
In recv_rev() previously all unacked_local_updates were deleted
as it was assumed that all of them have been acked at that point by
the revoke_and_ack itself. However this is not necessarily the case:
see new test case.
renamed log['unacked_local_updates'] to log['unacked_local_updates2']
to avoid breaking existing wallet files
pycryptodomex 3.7 implemented chacha20_poly1305 and chacha20,
and it is already used (although optionally) to speed up AES,
so we can remove cryptography and make pycryptodomex mandatory for LN
