feat: add scrapeTimeout to prometheus serviceMonitor endpoint

[mitchellwlatimer]

What issues does your PR fix?

• If metrics take longer than the current default of 10 seconds to scrape, no metrics are collected.
• To change this value, have to patch the service monitor or edit the yaml after each deployment.
• In my use case, the average scrape duration is 8 seconds and sometimes takes above 10 seconds leaving gaps in the metrics and I have to patch the service monitor with a scrape timeout set to 20 seconds.

What does your PR do?

Give users the ability to edit the scrape timeout to their desired setting if needed, while keeping the default of 10 seconds. In the documentation, the endpoint scrape timeout is set to the prometheus global scrape timeout of 10 seconds.

Checklist

For all Pull Requests

• [ ] Commits are signed off
• [ ] Commits have semantic messages
• [ ] Documentation updated
• [ ] Passes ct linting

For releasing ONLY

• [ ] Chart.yaml version bumped
• [ ] CHANGELOG.md updated

[stale[bot]]

This issue has been automatically marked as stale because it has not had activity in 60 days. It will be closed in 7 days if no further activity occurs.

Thank you for your contributions.

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