Add missing virtual destructors

[ivanpauno]

Same idea as ros2/rclcpp#1149.

There's an "overloaded virtual" warning that I'm ignoring in order to avoid breaking API now.
We should fix that in the future.

[ivanpauno]

Jobs config:

• build: --packages-up-to rviz2 rviz_default_plugins rviz_rendering rviz_rendering_tests rviz_visual_testing_framework
• test: --packages-select rviz2 rviz_default_plugins rviz_rendering rviz_rendering_tests rviz_visual_testing_framework

Jobs:

• Linux
• Linux-aarch64
• macOS
• Windows

[ivanpauno]

Retriggering linux job to confirm linters are happy:

• Linux

[ivanpauno]

Linter failures were fixed and retested on Linux, besides that all the jobs were greenish.
@jacobperron @wjwwood is this gtg?

[wjwwood]

I guess so, needs a second review. I just made a release of rviz, but I can roll another.

[wjwwood]

I believe this one also does not break API (adding the virtual destructor could be seen as that, but it's a corner case because no one who was calling it before would now have an issue, but I'm open to being convinced otherwise on that one).

[ivanpauno]

I don't think it breaks API, but it breaks ABI. So, it can't be backported in the future.

[wjwwood]

Yeah, sorry I wasn't suggesting we push it for the patch release, I just was sort of commenting on how the version number would change (also low risk for (re)testing).

[jacobperron]

LGTM

I'm okay with adding this to the initial Foxy release.