Support methods (CALL) in codegen

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Issue details

Schema may define methods. For example consider getKubeconfig method in EKS provider.

$ curl https://raw.githubusercontent.com/pulumi/pulumi-eks/v0.37.1/provider/cmd/pulumi-resource-eks/schema.json -o ~/schemas/pulumi-eks-v0.37.1.json

jq ".resources[\"eks:index:Cluster\"].methods" ~/schemas/pulumi-eks-v0.37.1.json 
{
  "getKubeconfig": "eks:index:Cluster/getKubeconfig"
}


$ jq ".functions[\"eks:index:Cluster/getKubeconfig\"]" ~/schemas/pulumi-eks-v0.37.1.json

{
  "description": "Generate a kubeconfig for cluster authentication that does not use the default AWS credential provider chain, and instead is scoped to the supported options in `KubeconfigOptions`.\n\nThe kubeconfig generated is automatically stringified for ease of use with the pulumi/kubernetes provider.\n\nSee for more details:\n- https://docs.aws.amazon.com/eks/latest/userguide/create-kubeconfig.html\n- https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-role.html\n- https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-profiles.html",
  "inputs": {
    "properties": {
      "__self__": {
        "$ref": "#/resources/eks:index:Cluster"
      },
      "profileName": {
        "type": "string",
        "description": "AWS credential profile name to always use instead of the default AWS credential provider chain.\n\nThe profile is passed to kubeconfig as an authentication environment setting."
      },
      "roleArn": {
        "type": "string",
        "description": "Role ARN to assume instead of the default AWS credential provider chain.\n\nThe role is passed to kubeconfig as an authentication exec argument."
      }
    },
    "required": [
      "__self__"
    ]
  },
  "outputs": {
    "properties": {
      "result": {
        "type": "string"
      }
    },
    "required": [
      "result"
    ]
  }
}

We currently skip generating code for these. Instead we should generate instance methods on the appropriate resource class. For an example how this maps to a comparable language, consider this code in C#:

https://github.com/pulumi/pulumi-eks/blob/master/dotnet/Cluster.cs#L113

Affected area/feature

Start by examining the schema.json example, especially resource methods and the corresponding function inputs and outputs. Compare the requested mapping with pulumi-eks's dotnet/Cluster.cs at line 113; done means generated Java resource classes expose instance methods for schema-defined CALL methods.