Add additional endpoint configuration for ServiceMonitor

[jmonson]

Issue

Added additional endpoint configuration for ServiceMonitor

Description of changes

Added the following configuration options for ServiceMonitor:

  scrapeTimeout:
  # If set overrides the _Prometheus_ default scheme.
  scheme:
  # Configure the `ServiceMonitor` [TLS config](https://github.com/coreos/prometheus-operator/blob/master/Documentation/api.md#tlsconfig).
  tlsConfig: {}
  # Provide a bearer token file for the `ServiceMonitor`.
  bearerTokenFile:
  # [Relabel configs](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#relabel_config) to apply to samples before ingestion.
  relabelings: []
  # [Metric relabel configs](https://prometheus.io/docs/prometheus/latest/configuration/configuration/#metric_relabel_configs) to apply to samples before ingestion.
  metricRelabelings: []

Checklist

• Added/modified documentation as required (such as the README.md for modified charts)
• Incremented the chart version in Chart.yaml for the modified chart(s)
• Manually tested. Describe what testing was done in the testing section below
• Make sure the title of the PR is a good description that can go into the release notes

Testing

Manually tested helm deployments with and without changes to values in serviceMonitor section.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.