Allow FetchContent_MakeAvailable() to try a call to
find_package() first, or redirect a find_package() call to
FetchContent_MakeAvailable(). The user can set variables
to control which of these are allowed or tried by default.
Fixes: #21687
Extend the feature added by commit d7b18895bc (cmake: Add filtered
debug-find options, 2021-12-07, v3.23.0-rc1~217^2) to enable debug
output for `find_*` calls within a find module or cmake package
configuration file.
Fixes: #23211