Feat: Add option to specify resources and tolerations

[jpambrun]

I don't have a good idea of what that would look like and it may well be out of scope, but my build pods are getting evicted. It would be nice to be able to pass cpu, mem and toleration.

In case others are interested, for now I have hardcoded what I needed in `kubectl-build with:

{
  "spec": {
    "hostPID": true,
    "hostNetwork": true,
    "containers": [
      {
        "securityContext": {
          "privileged": true
        },
        "image": "$image",
        "name": "kaniko",
        "stdin": true,
        "stdinOnce": true,
        "terminationMessagePath": "/dev/termination-log",
        "terminationMessagePolicy": "File",
        "args": $args,
        "volumeMounts": $volumemounts,
        "resources": {
          "requests":{
            "memory": "10Gi",
            "cpu": "8000m"
          },"limits":{
            "memory": "10Gi",
            "cpu": "8000m"
          }
        }
      }
    ],
    "tolerations":[{
      "key": "dedicated/highcpu",
      "operator": "Exists"
    }],
    "volumes": $volumes
  }
}