Add docs for Dev Containers

[ruffsl]

Related:

• https://github.com/ros-planning/navigation2/pull/3482

TODO:

• [x] markdown -> restructuredtext
• [x] refactor docker build instructions

[ruffsl]

@SteveMacenski , here is some documentation on my devcontainer work that we discussed over the previous Nav2 meeting.

[ruffsl]

We can save the restructuredtext for last, and I'll refactor docker build instructions based on feedback of what is written thus far.

[ruffsl]

Starting as 1c3996f , I've refactored the build and docker instructions.

As this PR is getting rather large, I think I'll split the devcontainer visualization docs to a seperate PR.

[ruffsl]

Current layout:

[SteveMacenski]

It looks like your changes broke the mechanism where artifacts are generated so I can see the output and website files in circleci https://app.circleci.com/pipelines/github/ros-planning/navigation.ros.org/1676/workflows/5e58a602-fac9-421b-993b-abd9d0e0dfaa/jobs/1985/artifacts. The job has no recorded artifacts.