Support of googletest using colcon [12009] (backport #2054)

[mergify]

This is an automatic backport of pull request #2054 done by Mergify.
Cherry-pick of 4f9f7e9 has failed:

On branch mergify/bp/2.1.x/pr-2054
Your branch is up to date with 'origin/2.1.x'.

You are currently cherry-picking commit 4f9f7e98e.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   cmake/common/gtest.cmake
	deleted:    cmake/modules/FindGMock.cmake
	modified:   colcon.pkg
	modified:   test/CMakeLists.txt
	modified:   test/realtime/mutex_testing_tool/CMakeLists.txt
	modified:   test/unittest/CMakeLists.txt
	modified:   test/unittest/dds/participant/CMakeLists.txt
	modified:   test/unittest/dds/subscriber/CMakeLists.txt
	modified:   test/unittest/dds/topic/CMakeLists.txt
	modified:   test/unittest/rtps/builtin/CMakeLists.txt
	modified:   test/unittest/rtps/discovery/CMakeLists.txt
	modified:   test/unittest/rtps/history/CMakeLists.txt
	modified:   test/unittest/rtps/reader/CMakeLists.txt
	modified:   test/unittest/security/cryptography/CMakeLists.txt
	modified:   test/unittest/security/logging/CMakeLists.txt

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   examples/C++/DDS/DeadlineQoSExample/CMakeLists.txt
	both modified:   examples/C++/DeadlineQoSExample/CMakeLists.txt
	both modified:   test/blackbox/CMakeLists.txt
	both modified:   test/communication/CMakeLists.txt
	both modified:   test/performance/CMakeLists.txt
	both modified:   test/performance/latency/CMakeLists.txt
	both modified:   test/performance/throughput/CMakeLists.txt
	both modified:   test/performance/video/CMakeLists.txt
	both modified:   test/profiling/CMakeLists.txt
	both modified:   test/realtime/CMakeLists.txt
	deleted by us:   test/unittest/dds/collections/CMakeLists.txt
	deleted by us:   test/unittest/dds/core/condition/CMakeLists.txt
	deleted by us:   test/unittest/dds/core/entity/CMakeLists.txt
	both modified:   test/unittest/dds/publisher/CMakeLists.txt
	both modified:   test/unittest/dds/status/CMakeLists.txt
	both modified:   test/unittest/dynamic_types/CMakeLists.txt
	both modified:   test/unittest/logging/CMakeLists.txt
	deleted by us:   test/unittest/logging/log_macros/CMakeLists.txt
	both modified:   test/unittest/rtps/common/CMakeLists.txt
	both modified:   test/unittest/rtps/flowcontrol/CMakeLists.txt
	both modified:   test/unittest/rtps/network/CMakeLists.txt
	both modified:   test/unittest/rtps/persistence/CMakeLists.txt
	both modified:   test/unittest/rtps/resources/timedevent/CMakeLists.txt
	both modified:   test/unittest/rtps/security/CMakeLists.txt
	both modified:   test/unittest/rtps/writer/CMakeLists.txt
	both modified:   test/unittest/security/accesscontrol/CMakeLists.txt
	both modified:   test/unittest/security/authentication/CMakeLists.txt
	deleted by us:   test/unittest/statistics/dds/CMakeLists.txt
	deleted by us:   test/unittest/statistics/rtps/CMakeLists.txt
	both modified:   test/unittest/transport/CMakeLists.txt
	both modified:   test/unittest/utils/CMakeLists.txt
	both modified:   test/unittest/xmlparser/CMakeLists.txt
	both modified:   test/unittest/xtypes/CMakeLists.txt
	both modified:   test/xtypes/CMakeLists.txt

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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[richiprosima]

Can't set status; build failed.

[JLBuenoLopez]

Closed in favor of #2852