XWIKI-22936: XWiki.SearchSuggestCode is not cached

[manuelleduc]

Jira URL

https://jira.xwiki.org/browse/XWIKI-22936

Changes

Description

• provide server side cache headers and invalidation logic
• for now the logic is local to XWiki.SearchSuggestCode but it should be possible to generalize to make it easier to reuse in other cases

Clarifications

Screenshots & Video

Executed Tests

Expected merging strategy

• Prefers squash: Yes
• Backport on branches:
  *

[manuelleduc]

@michitux @tmortagne @mflorea do you see obvious limitations with what's proposed in this PR?
I feel like this is an interesting approach as it does not require modifying the client-side code.
Of course completely removing the re-validation request is nicer, but this option already allows removing need to transfer the response body through the network in many cases.

[michitux]

What we usually do I think is to put the version of the document in the URL - if we could add the version of the configuration in the URL, this whole code wouldn't be necessary and we could simply enable long caching. I wouldn't be sure that this improves anything as at the point where this code is executed, it shouldn't make a big difference if the small content or the header is returned.