Docs: SDK implementation matrixes

[Kalaiselvi84]

What type of PR is this?

Uncomment only one /kind <> line, press enter to put that in a new line, and remove leading whitespace from that line:

/kind breaking
/kind bug
/kind cleanup

/kind documentation

/kind feature
/kind hotfix
/kind release

What this PR does / Why we need it:
Updated the SDK functionality table of the Go, Rust, Unity, and Unreal with new functions for Counters and Lists.

Which issue(s) this PR fixes:

Work on #2716

Special notes for your reviewer:

[agones-bot]

Build Succeeded 👏

Build Id: 7b52073d-7f08-414e-92e8-70f6381490c6

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:1.37.0-dev-19bb8d6-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.37.0-dev-19bb8d6-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.37.0-dev-19bb8d6-linux-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.37.0-dev-19bb8d6-amd64
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.37.0-dev-19bb8d6-amd64
• Linux C++ SDK (build): agonessdk-1.37.0-dev-19bb8d6-amd64-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.37.0-dev-19bb8d6-amd64.zip

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

• https://19bb8d6-dot-preview-dot-agones-images.appspot.com/

To install this version:

• git fetch https://github.com/googleforgames/agones.git pull/3545/head:pr_3545 && git checkout pr_3545
• helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.37.0-dev-19bb8d6-amd64