[REP-2013] ROS 2 Rust Client Library Integration

Coming out of a recent thread on ROS Discourse I've started collecting information.

I'm looking to bikeshed a little on the REP title as I am not sure that client libraries is quite comprehensive. I started with that because that was the subject of the discourse post which prompted the REP but I think that we're going to get into covering:

adding new package build types
adding new programming language support to the rosidl pipeline
adding new language-specific package managers to rosdep(1)
incorporating a new client library into the official ROS build farm
adopting an incorporated client library as part of "the ros2 core"

So whoever can help me condense that down will be doing me a favor. So far my favorite is "ROS 2 Programming Language Ecosystem Support".

(1) I think there are caveats here which make this not strictly required or even recommended but I also don't see an easy development path which doesn't include it.

I think there are several things that are going to start in this REP draft and then hopefully be removed to project-specific documentation for elaboration such as how to add build types to colcon and bloom, or how to add language-specific package managers to rosdep.

Since I'm going to link this publicly shortly after opening let me just say that this is an incredibly preliminary draft and is thus

certainly incomplete
likely unclear in several places
possibly flat out incorrect about one or more things

With that in mind, I'm primarily seeking feedback from the ROS 2 core team about what else ought to be laid out in this document while I complete the draft. Once I feel like there is something legible here I think it will be easier for client library contributors and ROS community members to review and I'll drop the draft status of this PR and update posts requesting more feedback.

ros-infrastructure / rep

[REP-2013] ROS 2 Rust Client Library Integration #363