Add ServiceMonitor for scraping metrics using PrometheusOperator

[antoniomrfranco]

Description of the change

Adding ServiceMonitor resource to make it easy to scrape metrics using Prometheus operator.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• Jira issue referenced in commit message and/or PR title

Testing

• Installed kube-prometheus-stack and deployed a new sidecar with metrics.enabled=true and metrics.serviceMonitor.enabled=true
• Verified that Prometheus was pulling metrics from the sidecar:
  

[wcmjunior]

Please keep docs in alphabetical order to make it easier to read.