Basic Agones GameServer integration test

[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

What this PR does / Why we need it:

This integration test only tests that we can create a GameServer in an Agones cluster and connect to it, providing baseline functionality for further integration tests.

This includes making the Agones CRD values public such that they can be accessed from the integration tests.

Which issue(s) this PR fixes:

Work on #510

Special notes for your reviewer:

Found a missing Apache licence header when I was in here, so updated that too.

[markmandel]

Just a note to self: Cloud Build needs permission to create K8s rolebindings

---- sidecar::tests::gameserver_no_sidecar stdout ----
thread 'sidecar::tests::gameserver_no_sidecar' panicked at 'called `Result::unwrap()` on an `Err` value: Api(ErrorResponse { status: "Failure", message: "rolebindings.rbac.authorization.k8s.io is forbidden: User \"328742829241@cloudbuild.gserviceaccount.com\" cannot create resource \"rolebindings\" in API group \"rbac.authorization.k8s.io\" in the namespace \"1661705393\": requires one of [\"container.roleBindings.create\"] permission(s).", reason: "Forbidden", code: 403 })', agones/src/lib.rs:189:60
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- pod::tests::create_quilkin_pod stdout ----
thread 'pod::tests::create_quilkin_pod' panicked at 'called `Result::unwrap()` on an `Err` value: Api(ErrorResponse { status: "Failure", message: "rolebindings.rbac.authorization.k8s.io is forbidden: User \"328742829241@cloudbuild.gserviceaccount.com\" cannot create resource \"rolebindings\" in API group \"rbac.authorization.k8s.io\" in the namespace \"1661705394\": requires one of [\"container.roleBindings.create\"] permission(s).", reason: "Forbidden", code: 403 })', agones/src/lib.rs:189:60

Will do it when back in the office tomorrow.

[quilkin-bot]

Build Succeeded 🥳

Build Id: e1de24e2-57ae-4f3c-bf63-60ffaa9d1bfb

To build this version:

git fetch git@github.com:googleforgames/quilkin.git pull/580/head:pr_580 && git checkout pr_580
cargo build