Port interactive_marker_tutorials to ROS 2 (#53)

* Start ROS 2 port for interactive_marker_tutorials

* Updated CMakeLists.txt and package.xml
* Ported 'basic controls' tutorial code

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Port simple marker tutorial

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Port selection tutorial

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Port cube tutorial

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Port menu tutorial

Only spawn one cube since two seems redundant.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Remove point cloud tutorial

It doesn't appear to demonstrate anything special about interactive markers

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Port pong tutorial

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Update install location

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Refactor for consistency

* Use classes that inherit from node.
* Naming consistency.
* Move shared function to utilities header.
* Add missing includes.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Register pong as a component

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Add colcon ignore markers

So that colcon does not attempt to build packages that have not been ported to ROS 2.

Signed-off-by: Jacob Perron <jacob@openrobotics.org>

* Fix warnings on Windows

Signed-off-by: Jacob Perron <jacob@openrobotics.org>