cudf now leverages rapids-cmake to reduce CMake boilerplate (#9030)

rapids-cmake providies features such as dependency tracking, pre-configured CPM dependencies, and CUDA architecture detction.

Using those features allows cudf to reduce the amount of CMake
code it needs to maintain, and brings it inline with the rest
of RAPIDS.

Authors:
  - Robert Maynard (https://github.com/robertmaynard)

Approvers:
  - Jason Lowe (https://github.com/jlowe)
  - Mark Harris (https://github.com/harrism)

URL: #9030

build.sh

@@ -165,10 +165,10 @@ fi
 
 if buildAll || hasArg libcudf; then
     if (( ${BUILD_ALL_GPU_ARCH} == 0 )); then
-        CUDF_CMAKE_CUDA_ARCHITECTURES="-DCMAKE_CUDA_ARCHITECTURES="
+        CUDF_CMAKE_CUDA_ARCHITECTURES="-DCMAKE_CUDA_ARCHITECTURES=NATIVE"
         echo "Building for the architecture of the GPU in the system..."
     else
-        CUDF_CMAKE_CUDA_ARCHITECTURES=""
+        CUDF_CMAKE_CUDA_ARCHITECTURES="-DCMAKE_CUDA_ARCHITECTURES=ALL"
         echo "Building for *ALL* supported GPU architectures..."
     fi