Update docs for container specific workspace logs/post start scripts
MR: Pending
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## Description
This is a followup to this [thread](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/198027#note_2748695551). We added support for container specific post start events in this MR https://gitlab.com/gitlab-org/gitlab/-/merge_requests/198027+ along with organization of logs and post start scripts in container specific directories. We should update the workspace docs with this information.
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## Acceptance criteria
- [ ] Location of container specific logs documented
- [ ] Location of container specific scripts documented
## Implementation plan
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[Provide a high-level plan for implementation of this issue, including relevant technical and/or design details.]
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