Update the naming conventions for parameters in launch files

[xmfcx]

Checklist

• I've read the contribution guidelines.
• I've searched other issues and no duplicate issues were found.
• I've agreed with the maintainers that I can plan this task.

Description

Follow up from #223

Purpose

Update the naming conventions for namespaces and launch files following discussion in https://github.com/orgs/autowarefoundation/discussions/3171

Possible approaches

Update the documentation following up from #223

Definition of done

PR is merged covering the updates in the discussion.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity.