Upgrade to Python 3.11

[jwhitlock]

Python 3.11.0 was released October 24, 2022. We'll want to upgrade to Python 3.10 first (#2452) done!, and then ensure that our dependencies support Python 3.11.

Some of the new major new features and changes in Python 3.11 are:

General changes

• PEP 657 -- Include Fine-Grained Error Locations in Tracebacks
• PEP 654 -- Exception Groups and except*
• PEP 680 -- tomllib: Support for Parsing TOML in the Standard Library
• gh-90908 -- Introduce task groups to asyncio
• gh-34627 -- Atomic grouping ((?>...)) and possessive quantifiers (*+, ++, ?+, {m,n}+) are now supported in regular expressions.
• The Faster CPython Project is already yielding some exciting results. Python 3.11 is up to 10-60% faster than Python 3.10. On average, we measured a 1.22x speedup on the standard benchmark suite. See Faster CPython for details.

Typing and typing language changes

• PEP 673 -- Self Type
• PEP 646 -- Variadic Generics
• PEP 675 -- Arbitrary Literal String Type
• PEP 655 -- Marking individual TypedDict items as required or potentially-missing
• PEP 681 -- Data Class Transforms

### Tasks
- [ ] https://github.com/mozilla/fx-private-relay/issues/2452
- [ ] https://github.com/mozilla/fx-private-relay/issues/3126

[jwhitlock]

Django 3.2 doesn't support Python 3.11, so this is blocked by issue #3126. There may be others, but that's a good one to update if we can first.

[rafalkrupinski]

is this issue superseded by #3982?

[jwhitlock]

No, we update Python by one minor version at a time. #3982 (Update to Python 3.12) is blocked by this one.

[jwhitlock]

We've updated to Python 3.11 in production.