feat: Add 'grafana_address' attribute for logging pipelines

[adeatcu-ionos]

What does this fix or implement?

Fixes https://github.com/ionos-cloud/terraform-provider-ionoscloud/issues/556

Checklist

• [x] PR name added as appropriate (e.g. feat:/fix:/doc:/test:/refactor:)
• [x] Tests added or updated
• [x] Documentation updated
• [x] Changelog updated and version incremented (label: upcoming release)
• [ ] Github Issue linked if any
• [ ] Jira task updated

[sonarcloud[bot]]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
33.3% Duplication on New Code

See analysis details on SonarCloud