meta: add governance model and update code of conduct to CNCF

[markmandel]

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:

Document the project governance model based on the CNCF governance maintainer template (https://contribute.cncf.io/projects/best-practices/governance/templates/governance-maintainer/). Also migrate to the CNCF code of conduct.

Which issue(s) this PR fixes:

Work on #4421

Special notes for your reviewer:
N/A

[markmandel]

@agones-dev/approvers in particular -- please let me know if you see any issues or improvements on this. I feel like this is basically outlining what we do now (lazy consensus), but feel free to provide commentary.

[agones-bot]

Build Succeeded 🥳

Build Id: 7132215b-c039-4f17-b925-dc064ce1b31e

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:1.58.0-dev-83a9ef6
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.58.0-dev-83a9ef6
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.58.0-dev-83a9ef6-linux
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.58.0-dev-83a9ef6
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.58.0-dev-83a9ef6
• image: us-docker.pkg.dev/agones-images/ci/agones-processor:1.58.0-dev-83a9ef6
• Linux C++ SDK (build): agonessdk-1.58.0-dev-83a9ef6-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.58.0-dev-83a9ef6.zip

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

• https://83a9ef6-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/googleforgames/agones.git pull/4573/head:pr_4573 && git checkout pr_4573
helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.58.0-dev-83a9ef6

[lacroixthomas]

@agones-dev/approvers in particular -- please let me know if you see any issues or improvements on this. I feel like this is basically outlining what we do now (lazy consensus), but feel free to provide commentary.

Looking great !

[agones-bot]

Build Succeeded 🥳

Build Id: cd2c8c73-9809-4a60-80d0-122fbe1b784b

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:1.59.0-dev-50c682e
• image: us-docker.pkg.dev/agones-images/ci/agones-extensions:1.59.0-dev-50c682e
• image: us-docker.pkg.dev/agones-images/ci/agones-sdk:1.59.0-dev-50c682e-linux
• image: us-docker.pkg.dev/agones-images/ci/agones-ping:1.59.0-dev-50c682e
• image: us-docker.pkg.dev/agones-images/ci/agones-allocator:1.59.0-dev-50c682e
• image: us-docker.pkg.dev/agones-images/ci/agones-processor:1.59.0-dev-50c682e
• Linux C++ SDK (build): agonessdk-1.59.0-dev-50c682e-linux-arch_64.tar.gz
• SDK Server: agonessdk-server-1.59.0-dev-50c682e.zip

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

• https://50c682e-dot-preview-dot-agones-images.appspot.com/

To install this version:

git fetch https://github.com/googleforgames/agones.git pull/4573/head:pr_4573 && git checkout pr_4573
helm install agones ./install/helm/agones --namespace agones-system --set agones.image.registry=us-docker.pkg.dev/agones-images/ci --set agones.image.tag=1.59.0-dev-50c682e