Add support for HTTP QUERY method to CacheMiddleware/@cache_page

[Jacob Walls]

Sibling ticket for #37232, which is already advanced on the new features board. This ticket is not open for assignment until the contributors who have already reviewed and participated on #37232 have had a chance to indicate interest.

#37232 left caching out of scope. We should consider adding support for caching HTTP QUERY methods to the cache middleware if we can answer these questions:

• Cache key: I presume we need to append a hash of the request body to the cache key, without parsing.
• Re-reading: what happens when a view calls request.read()? This would cause RawPostDataException when trying to read the raw body again to calculate the cache key afterward. (Calculating the key after the view could happen on cold-caches.)
• Do we let RequestDataTooBig emanate from the cache middleware instead of the view? This could catch someone who has except RequestDataTooBig in a def post() decorated with @csrf_exempt that they are converting to def query(). Or do we treat the over-limit case as "don't cache" and let the view run? One way or the other we might need a backward incompatible change notice.