Copy code from nvidia-container-runtime

This change copies the cmd/nvidia-container-runtime, internal, and test
folders from github.com/NVIDIA/nvidia-container-runtime@8a63b4b34f3ce3b4167f0516aa3f7207ca280dfb

Signed-off-by: Evan Lezar <elezar@nvidia.com>

internal/oci/runtime.go

@@ -0,0 +1,23 @@
+/*
+# Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+*/
+
+package oci
+
+// Runtime is an interface for a runtime shim. The Exec method accepts a list
+// of command line arguments, and returns an error / nil.
+type Runtime interface {
+	Exec([]string) error
+}