docker: downgrade alpine to 3.13 again

See https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.14.0#faccessat2 ;
this maintains compatibility with older, buggy versions of docker and runc.
Alpine 3.13 is supported until 2022-11-01.

CHATHISTORY with nonexistent msgid should send empty batch

fix case where CS TRANSFER as an operator required acceptance

It was sending MESSAGE_ERROR, which was inappropriate. Send an empty batch
for now (this is at parity with the in-memory implementation).

Reported by @mogad0n. If a user had both operator privileges and
channel owner privileges, the CS TRANSFER would proceed as though
unprivileged, requiring acceptance by the receiving user. Fix this
to not require acceptance.

docker: Error response from daemon: failed to create shim: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "/ircd-bin/run.sh": permission denied: unknown.

See #1808

fix #1676, take 2

fix #1802

fix spurious "corrupt account creds" logline

Reported by @tacerus. This was most likely introduced by 8b2f6de3e.

Add a config option to suppress LUSERS

See #1676

Ensure the pagination window is full by making sure that every history item
gets a replay line in CHATHISTORY output, even TAGMSG.

This reverts commit 5bbee02fe6.

update 'docker kill' command

fix #1676

upgrade buntdb

Fix various pagination issues with CHATHISTORY; also undo #491
(msgid munging).

make `ergo genpasswd` warn for bad passwords

Resolves CVE-2021-42836, which probably didn't affect us, but we might as well
upgrade.

Send snomask for channel mode changes via SAMODE.

Fixes #1787

move signals code to utils/

factor out some shared code

document gamja

rename oragono.io/nope to ergo.chat/nope

Thanks to @cxxboy (#1788)

add # to disfavoredNameCharacters

update logo in /INFO response

Partially fixes #1679, not sure whether to police the relaymsg config or not

(based on 'slant' figlet font with some tweaks)

fix #1530