Merge topic 'imported-cxxmodules'

48ee946fdc cmExperimental: recycle the C++ modules API UUID
1a1806a71b gitlab-ci: declare `bmionly` support for modules where possible
457a12f3f9 Tests/RunCMake/CXXModules: add tests which use modules from imported targets
9b9ec70b54 Ninja: generate scanning and build rules for C++20 module synthetic targets
80ef50a191 CXXModules: add a variable for BMI-only compilation
80d6544398 cxxmodules: generate synthetic targets as an initial pass
3dc6676ecc cmSyntheticTargetCache: add a struct for synthetic target caching
cb356b540c cmCxxModuleUsageEffects: add a class to capture module usage effects
...

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: buildbot <buildbot@kitware.com>
Merge-request: !8535