Merge topic 'post-rel-dev'

be045c7c16 Configure CMake itself with policies through CMake 3.27
c5f1af1ffe export: Increase maximum policy version in exported files to 3.27
86d910ab73 Add deprecation warnings for policies CMP0126 and below

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !8858