[DNM] Configure TLS for Alertmanager

[vyzigold]

Now that COO and telemetry-operator finally support TLS for alertmanager, we can generate the certificates and configure TLS similar to all other services.

Jira: https://redhat.atlassian.net/browse/OSPRH-5177

Generated-By: Claude-Code claude-opus-4-6

[openshift-ci]

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[github-actions]

OpenStackControlPlane CRD Size Report

Metric	Value
CRD JSON size	350002 bytes (342KB)
Base branch size	364822 bytes
Change	-4.06%
Status	yellow — growing

Threshold reference

Color	Range	Meaning
🟢 green	< 300KB	Comfortable
🟡 yellow	300–400KB	Growing
🟠 orange	400–750KB	Concerning
🔴 red	> 750KB	Approaching 1.5MB etcd limit (cut in half to allow space for update)

[vyzigold]

This needs the related telemetry-operator PR and afterwards the operator dependency bump PR merged first to get the new telemetry-operator CRD fields used in this PR. I'm leaving this as a draft until then.

[vyzigold]

The related telemetry-operator PR: openstack-k8s-operators/telemetry-operator#949

[centosinfra-prod-github-app]

Build failed (check pipeline). Post recheck (without leading slash)
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you rerun jobs.

https://gateway-cloud-softwarefactory.apps.ocp.cloud.ci.centos.org/zuul/t/rdoproject.org/buildset/0d438c9c9feb4e7199d3b489491e31cd

❌ openstack-k8s-operators-content-provider FAILURE in 9m 27s
⚠️ podified-multinode-edpm-deployment-crc SKIPPED Skipped due to failed job openstack-k8s-operators-content-provider
⚠️ cifmw-crc-podified-edpm-baremetal SKIPPED Skipped due to failed job openstack-k8s-operators-content-provider
⚠️ openstack-operator-tempest-multinode SKIPPED Skipped due to failed job openstack-k8s-operators-content-provider
⚠️ openstack-operator-edpm-baremetal-minor-update SKIPPED Skipped due to failed job openstack-k8s-operators-content-provider