CBD-6348: Merge remote-tracking branch 'couchbase/neo' into trinity

Merged with -s ours as the changes are already present in trinity

* couchbase/neo:
  CBD-6348: [BP] [C++20] Add SerialisedDocKey::operator== ...
  CBD-6348: [BP] Various fixes needed to build with C++20
  CBD-6348: [BP] Fix problems with nlohmann and gtest
  CBD-6348: Remove class name in member declaration
  CBD-6348: [BP] Disable fmt format check for WIN32

Change-Id: I29f6488524f04d3c00c05b6ac87918243cbd56c1

Author: trondn