Add integration guide for Google Cloud Managed Service for Prometheus

[zmerlynn]

Adds a guide plus two additional manifests to help with install for Managed Prometheus. Install tested on 1.25 Autopilot.

Gated on 1.30 release because I made a handful of changes to Grafana charts to accomodate GMP - the charts won't work in previous versions, but the metric collection would be fine. Regardless, we're super close to the release date anyways, so I think it's fine to gate it.

Towards #2777 indirectly (the standard Prometheus install doesn't work on Autopilot).

[agones-bot]

Build Succeeded 👏

Build Id: 73d955a9-4f2c-454f-81ca-7f61e8c409db

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.30.0-89d290e-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.30.0-89d290e-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.30.0-89d290e-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.30.0-89d290e-amd64
• Linux C++ SDK (build): agonessdk-1.30.0-89d290e-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.30.0-89d290e-amd64.zip

A preview of the website (the last 30 builds are retained):

• https://89d290e-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2990/head:pr_2990 && git checkout pr_2990
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.30.0-89d290e-amd64

[zmerlynn]

Thanks for the review, @roberthbailey! PTAL

[roberthbailey]

Looks good - just waiting for the website to render to make sure the links all work as expected.

[zmerlynn]

Looks like https://0774a91-dot-preview-dot-agones-images.appspot.com/site/ is available now.

[agones-bot]

Build Succeeded 👏

Build Id: da082780-e3c7-4348-8e5e-4d109e13c0e8

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.30.0-0774a91-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.30.0-0774a91-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.30.0-0774a91-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.30.0-0774a91-amd64
• Linux C++ SDK (build): agonessdk-1.30.0-0774a91-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.30.0-0774a91-amd64.zip

A preview of the website (the last 30 builds are retained):

• https://0774a91-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2990/head:pr_2990 && git checkout pr_2990
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.30.0-0774a91-amd64

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: roberthbailey, zmerlynn

The full list of commands accepted by this bot can be found here.

The pull request process is described here

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• OWNERS [roberthbailey]

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[google-oss-prow]

New changes are detected. LGTM label has been removed.

[agones-bot]

Build Succeeded 👏

Build Id: 426f18d8-1b5c-49a3-a7cd-f524458073fe

The following development artifacts have been built, and will exist for the next 30 days:

• image: us-docker.pkg.dev/agones-images/ci/agones-controller:1.30.0-dee60ba-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.30.0-dee60ba-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.30.0-dee60ba-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.30.0-dee60ba-amd64
• Linux C++ SDK (build): agonessdk-1.30.0-dee60ba-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.30.0-dee60ba-amd64.zip

A preview of the website (the last 30 builds are retained):

• https://dee60ba-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/2990/head:pr_2990 && git checkout pr_2990
• helm install agones ./install/helm/agones --namespace agones-system --agones.image.release=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.30.0-dee60ba-amd64