Add proto rpc interface for cli

This commit adds proto rpc definitions for the communication needed for
the CLI interface.
This will allow us to move the rest of the CLI interface over to gRPC
and in the future allow remote access

proto/headscale/v1/namespace.proto

@@ -0,0 +1,50 @@
+syntax = "proto3";
+package headscale.v1;
+option  go_package = "github.com/juanfont/headscale/gen/go/v1";
+
+import "google/protobuf/timestamp.proto";
+
+message Namespace {
+    string                    id         = 1;
+    string                    name       = 2;
+    google.protobuf.Timestamp created_at = 3;
+}
+
+message GetNamespaceRequest {
+    string name = 1;
+}
+
+message GetNamespaceResponse {
+    Namespace namespace = 1;
+}
+
+message CreateNamespaceRequest {
+    string name = 1;
+}
+
+message CreateNamespaceResponse {
+    Namespace namespace = 1;
+}
+
+message RenameNamespaceRequest {
+    string old_name = 1;
+    string new_name = 2;
+}
+
+message RenameNamespaceResponse {
+    Namespace namespace = 1;
+}
+
+message DeleteNamespaceRequest {
+    string name = 1;
+}
+
+message DeleteNamespaceResponse {
+}
+
+message ListNamespacesRequest {
+}
+
+message ListNamespacesResponse {
+    repeated Namespace namespaces = 1;
+}