Support GameServer.Spec.SdkServer.LogLevel "Trace"

[markmandel]

What happened:

I wanted to see some trace level debugging in the sidecar -- and I couldn't 😭

What you expected to happen:

Be able to use trace in the GameServer.Spec.SdkServer.LogLevel field.

How to reproduce it (as minimally and precisely as possible):

Try it! It won't validate!

Anything else we need to know?:

Environment:

• Agones version: dev
• Kubernetes version (use kubectl version):
• Cloud provider or hardware configuration:
• Install method (yaml/helm):
• Troubleshooting guide log(s):
• Others: