chore: add test and docs for metrics

[xeniape]

Description

Part of stackabletech/issues#735
Trino already provides built-in Prometheus metrics per default. This PR adds testing the metrics endpoint and some documentation.

--- FAIL: kuttl (2045.00s)
    --- FAIL: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_trino-451_hive-3.1.3_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (417.36s)
        --- PASS: kuttl/harness/smoke_trino-470_hive-4.0.1_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (435.47s)
        --- PASS: kuttl/harness/smoke_trino-476_hive-4.0.1_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (426.37s)
        --- FAIL: kuttl/harness/smoke_trino-476_hive-3.1.3_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (1182.69s)
        --- FAIL: kuttl/harness/smoke_trino-470_hive-3.1.3_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (1110.19s)
        --- PASS: kuttl/harness/smoke_trino-451_hive-4.0.1_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (426.83s)
FAIL
ERROR:root:kuttl failed

--- PASS: kuttl (409.49s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_trino-470_hive-3.1.3_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (409.48s)
PASS

--- PASS: kuttl (373.74s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_trino-476_hive-3.1.3_opa-1.4.2_hdfs-3.4.1_zookeeper-3.9.3_openshift-false (373.73s)
PASS

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

Author

• Changes are OpenShift compatible
• CRD changes approved
• CRD documentation for all fields, following the style guide.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

• Feature Tracker has been updated
• Proper release label has been added
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[razvan]

The AWS metrics test will not work like this but I'm personally also fine if you remove it.

[razvan]

Suggested change

	host_coordinator_0 = (
	"http://trino-coordinator-default-0.trino-coordinator-default."
	+ namespace
	+ ".svc.cluster.local"
	)
	host_worker_0 = (
	"http://trino-worker-default-0.trino-worker-default."
	+ namespace
	+ ".svc.cluster.local"
	)
	host_coordinator_0 = f"http://trino-coordinator-default-0.trino-coordinator-default.{namespace}.svc.cluster.local"
	host_worker_0 = f"http://trino-worker-default-0.trino-worker-default.{namespace}.svc.cluster.local"

[razvan]

These are the wrong auth credentials. On AWS admin/admin should work. Maybe also bob/bob.

[razvan]

Needs https on AWS.