Add USB CDC transport example for ESP-IDF (Humble)

[Mohamed-Sejid]

adds a micro-ROS example for the ESP-IDF environment on the humble branch on how to use the USB CDC transport for communication in the same way that the examples are available on the kilted branch

[mergify]

@Mohamed-Sejid, all pull requests must be targeted towards the rolling development branch.
Once merged into rolling, it is possible to backport to humble, but it must be in rolling
to have these changes reflected in new distributions.

Can be ignored for this PR as it's essentially a backport.

[Narukara]

🤔 Do we actually want to add this? It was intentionally not added to humble before. #263 (comment)

Currently, CI builds this example on humble. We can make it skip that.

@EugenioCollado @Amronos

[Amronos]

I think the intention behind not backporting it before was to avoid a maintenance burden.
That should no longer be a problem, as 3 of us are maintaining the software right now. Additionally, Humble is going to stay for another year.
Perhaps we should just reopen #263 instead.

[Narukara]

I think the intention behind not backporting it before was to avoid a maintenance burden. That should no longer be a problem, as 3 of us are maintaining the software right now. Additionally, Humble is going to stay for another year. Perhaps we should just reopen #263 instead.

OK. I will check the differences between this PR and the original backport.