Add ROS2 Support (minimal) to work in conjunction with ROS1

[vinnnyr]

This adds:

1. Dockerfile to test building in ROS1 and ROS2
2. Some unit tests for the conversor function, that get built in ROS2
3. CMake and Package.xml changes to support ROS1 and ROS2 to live together simultaneously.

I used techniques found in this repo as the pattern for getting ROS1 and ROS2 to live simultaneously.
https://github.com/luxonis/depthai-ros

Note that the launch / RVIZ functionality is not recreated at the moment.

Maybe it makes sense to have a separate branch to merge this change in (besides master ) while we get comfortable with these changes.

I have tested this builds in ROS1 (via the dockerfile), and tested the build and unit tests for ROS2.

[vinnnyr]

If wanted I will happily PR Dockerfile.noetic separately to master so that it can be used by others without being blocked by this PR build.

[Gonzalo-Mier]

Hi @vinnnyr,
Really nice PR. Thank you really much for your work. I will create a new branch and we can work there.

[Gonzalo-Mier]

We can continue working on the branch add-ros2-support

[vinnnyr]

Awesome thanks! Shall I close this PR then?

[Gonzalo-Mier]

I guess we can close it. Thank you again!