Add SMP template port and example (#900)

* Add SMP template port and example
* Add readme file for smp configuration
* Update SMP build flow and add CI build

---------

Co-authored-by: Soren Ptak <ptaksoren@gmail.com>
Co-authored-by: Rahul Kar <118818625+kar-rahul-aws@users.noreply.github.com>

.github/workflows/kernel-demos.yml

@@ -111,6 +111,13 @@ jobs:
           cmake -S . -B build
           cmake --build build
 
+      - name: Build CMake SMP Example Demo
+        shell: bash
+        working-directory: examples/cmake_example
+        run: |
+          cmake -S . -B build -DFREERTOS_SMP_EXAMPLE=1
+          cmake --build build
+
   MSP430-GCC:
     name: GNU MSP430 Toolchain
     runs-on: ubuntu-latest