update troubleshooting guide

[a-mccarthy]

Updates to troubleshooting guide to include more details on common issues.

To do:

• Align on formatting for presenting troubleshooting info. Do we want to stick with current format: Issue, Observation, Root Cause, Actions? I feel like its a bit too rigid of a for some of the new content. For example, a root cause may depend on the users system, so that section could lead to more confusion. Also to me issue/observation are very similar sections, and could be removed in favor of having the information as the fist paragraph under the section title.

[a-mccarthy]

@tariq1890 do we want to point folks to the github repo for filing issues if they can't find their issue on this page? Is the must gather script the best way we want folks to share info about their system in a github issue?

[tariq1890]

So the troubleshooting guide is not meant to be an exhaustive list of gpu-operator issues. Users could either file a GitHub issue or they are free to contribute to the docs if they feel the troubleshooting guide could add more issues

[github-actions]

Documentation preview

https://nvidia.github.io/cloud-native-docs/review/pr-216

[tariq1890]

Do we want to stick with current format: Issue, Observation, Root Cause, Actions?

I am definitely open to a better format. This was the format I had gone with when creating the first draft of the troubleshooting guide. If there is a better and more reader-friendly format, we should definitely switch to that.

[tariq1890]

Thanks for this PR, @a-mccarthy !