Add QUERY HTTP method

[desiderantes]

Fixes #32975

[bclozel]

Thanks for the initial efforts @desiderantes - at this point the linked issue hasn't been triaged and is very unlikely to make it to the 6.2 version. We'll need thorough reviews and testing for this one.

Note that since this is a new HTTP method and new feature, I don't think we will want to introduce it everywhere and for all variants of our web support. For example, I'm wondering if surfacing it as a first class citizen in RestTemplate is a good idea. Maybe using the exchange variants is good enough here?

[desiderantes]

@bclozel Yes no worries, just wanted to get this started somehow. I do think that supporting a new HTTP Method shouldn't be half-hearted, and ideally it would mean support everywhere, not just in the basic HttpMethod class

[bclozel]

@desiderantes We're trying to balance maintenance and evolution, especially around parts that have been very stable for a long time. Adding this method as first class in WebClient and RestClient makes sense, but RestTemplate has been "feature complete" for a long time now and we don't want to expand its main surface API.

[bclozel]

Marking as blocked for now because #32975 (comment)