Add two examples for CMake

Signed-off-by: Kevin Mittman <kmittman@nvidia.com>

cmake/1_FindCUDAToolkit/CMakeLists.txt

+cmake_minimum_required (VERSION 3.17)
+project (HelloWorld)
+set(CUDAToolkit_ROOT "${CMAKE_BINARY_DIR}/extracted/cuda")
+find_package(CUDAToolkit)

cmake/1_FindCUDAToolkit/README.md

+# CMake example 1: FindCUDAToolkit
+
+FindCUDAToolkit is the recommended module for importing CUDA components into the CMake build system (3.17 and newer).
+
+The path to the extraction location can be specified with `-DCUDAToolkit_ROOT=$PWD/extracted` or the `CUDAToolkit_ROOT` environmental variable
+
+> **NOTE:** The minimum required components for the FindCUDAToolkit module are `cuda_cudart` and `cuda_nvcc`.
+
+## Commands
+
+```shell
+mkdir extracted
+cd extracted
+tar -xf cuda_nvcc-linux-x86_64-*-archive.tar.xz
+tar -xf cuda_nvcc-linux-x86_64-*-archive.tar.xz
+mkdir cuda
+rsync -av *-archive/ cuda/
+cd ..
+cmake .
+```

cmake/2_ExternalProject/CMakeLists.txt

+cmake_minimum_required (VERSION 3.17)
+project (CUDA)
+set(CUDAToolkit_ROOT "${CMAKE_BINARY_DIR}/extracted/cuda")
+find_package(CUDAToolkit)

cmake/2_ExternalProject/README.md

+# CMake example 2: ExternalProject
+
+The ExternalProject_Add module downloads archives from a URL
+
+## Commands
+
+```shell
+cmake .
+make
+```