Add standalone C driver guide

Author: awvwgk

.github/workflows/examples.yml

@@ -17,6 +17,9 @@ jobs:
       matrix:
         toolchain: ["openmp", "mpi"]
         gauxc: ["release", "main"]
+        example: ["cpp/gauxc_integration", "c/gauxc_integration"]
+
+    name: "${{ matrix.example }} (gauxc ${{ matrix.gauxc }} ${{ matrix.toolchain }})"
 
     steps:
     - uses: actions/checkout@v4
@@ -66,7 +69,7 @@ jobs:
       run: >-
         cmake
         -B build_example
-        -S skala/examples/cpp/gauxc_integration
+        -S skala/examples/${{ matrix.example }}
         -G Ninja
         -DSkala_GauXC_ENABLE_OPENMP=${{ matrix.toolchain == 'openmp' }}
         -DSkala_GauXC_ENABLE_MPI=${{ matrix.toolchain == 'mpi' }}