Expand debugging services tips

[paurullan]

During my first tests I got a lot of trouble for having non-kubernetes compatible Alpine linux images. Also, one time I incorrectly wrote the service selectors.

This PR is just an expansion for those papercuts.

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[johndmulhausen]

• Does the service have a selector and is it spelled correctly?

[bgrant0607]

cc @kubernetes/sig-network

[paurullan]

I signed it! as Advanced Programming Solutions SL (APSL)

[paurullan]

@johndmulhausen I added and example of both questions. Is there anything else to improve?

[kelseyhightower]

@paurullan Can you address the issues related to DNS and alpine linux? I'll be happy to review this after that's done. Overall this look pretty good.

[pwittrock]

@paurullan Friendly bump.

[pwittrock]

@devin-donnelly Would be good to either close this, or merge it and fix the issues as a follow up. Would you be able to drive this?

[paurullan]

@pwittrock @kelseyhightower sorry for the delay, I had a disconnection for the whole August.
I addressed the comments about the DNS.