Fixes #2048

I assumed gorilla validated UTF8 for incoming text messages. In fact, the
documentation states:

>It is the application's responsibility to ensure that text messages
>are valid UTF-8 encoded text.

and this applies to both incoming and outgoing messages. Consequently,
even when enforce-utf8 is enabled, it was possible to send invalid UTF8
to Ergo inside a websocket text frame. This data would be incorrectly
considered valid UTF8, and could be relayed to other clients, including
to websocket clients inside a text frame. The resulting frame would violate
the websocket protocol, causing web clients to be disconnected.

final updates for v2.11.0-rc1

Fix SAREGISTER short help in SAVERIFY command

* draft changelog for v2.11.0-rc1

* add another entry

* copyedits

change default casefolding to ascii

See discussion on #1718

Provide a nondestructive stack trace dump option even when the http pprof
listener is disabled

TAGMSG should not get automatic RPL_AWAY replies

document that persistent history is not affected by buffer limits

fix #1850

Add WHO responses for services

re-add draft/CHATHISTORY 005

Kiwi expects it due to https://github.com/kiwiirc/kiwiirc/pull/1244 , but
the corresponding spec change only altered the cap name, not the 005 name.

fix CHATHISTORY 005 token name

Unclear where we got draft/CHATHISTORY from, it looks like the merged drafts
have always used unprefixed CHATHISTORY as the token name.

* fix #2002

`CS AMODE #channel +f nickname` is invalid, but was being accepted
incorrectly.

* simplify logic

Use ratified extended-monitor cap name

https://github.com/ircv3/ircv3-specifications/pull/508

Update MANUAL.md

- Change instructions to place the script from `post` to `deploy` which will only update the certificate and key IF the renewal is successful.

fix #1996

According to the de facto standard, `AWAY :\r\n` is equivalent to `AWAY\r\n`.
Our behavior was inconsistent before, now it consistently matches the de facto
standard.

replace some utils.Semaphore with (*sync.Mutex).TryLock

See #1994

exempt a configurable number of MARKREAD commands from fakelag

fix #1991

WHO <nickname> should not respect +i

use new aligned atomic types everywhere

/UBAN LIST explicitly states 'indefinite' durations for Klines/Dlines

See 69448b13a1 / #1969; the compiler can now ensure that a uint64
intended for atomic access is always aligned to a 64-bit boundary.
Convert atomic operations on uint32s and pointers as well.

upgrade go to 1.19