Clean up namespaces - part 4 (backport #653)

[mergify]

Splitting the work created from @mjcarroll in #502. This is the final patch modifying the rest of the files.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

---

This is an automatic backport of pull request #653 done by Mergify.

[mergify]

Cherry-pick of 14b1f20 has failed:

On branch mergify/bp/gz-transport14/pr-653
Your branch is up to date with 'origin/gz-transport14'.

You are currently cherry-picking commit 14b1f20.
  (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:   parameters/src/Client.cc
	modified:   parameters/src/Registry.cc
	modified:   parameters/src/result.cc
	modified:   src/AdvertiseOptions.cc
	modified:   src/Clock.cc
	modified:   src/Discovery.cc
	modified:   src/Helpers.cc
	modified:   src/MessageInfo.cc
	modified:   src/NetUtils.cc
	modified:   src/Node.cc
	modified:   src/NodeOptions.cc
	modified:   src/NodeOptionsPrivate.hh
	modified:   src/NodePrivate.hh
	modified:   src/NodeShared.cc
	modified:   src/NodeSharedPrivate.hh
	modified:   src/Publisher.cc
	modified:   src/SubscribeOptions.cc
	modified:   src/SubscribeOptionsPrivate.hh
	modified:   src/SubscriptionHandler.cc
	modified:   src/TopicStatistics.cc
	modified:   src/TopicUtils.cc
	modified:   src/Uuid.cc
	modified:   src/cmd/gz.cc

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   parameters/src/Utils.cc

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