feat: add extra jmx metrics

[caiopavanelli]

What this PR does / why we need it:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Verify the work you plan to merge addresses an existing issue (If not, open a new one) (required)
• Check your branch with helm lint (required)
• Update version in Chart.yaml according semver rules (required)
• Substitute annotations section in Chart.yaml annotating implementations (useful for Artifacthub changelog) (required)
• Update chart README using helm-docs (required)

Which issue(s) this PR fixes:

Fixes #211

Special notes for your reviewer:

The extraMetrics parameter would allow the export of extra jmx metrics like the following.

jmxExporter:
  extraMetrics: |
    - pattern: trino.execution<name=QueryManager><>ExecutionTime.OneMinute.P50
      name: trino_execution_time_one_minute_p50

    - pattern: trino.execution<name=QueryManager><>ExecutionTime.OneMinute.P90
      name: trino_execution_time_one_minute_p90

    - pattern: trino.execution<name=QueryManager><>ExecutionTime.OneMinute.P99
      name: trino_execution_time_one_minute_p99