Donwloading kokkos and installing tbb is now automatic

cmake/preReq.cmake

@@ -0,0 +1,44 @@
+if(pFlow_STD_Parallel_Alg)
+    # Check if libtbb-dev is installed
+    execute_process(
+        COMMAND dpkg -s libtbb-dev
+        RESULT_VARIABLE TBB_IS_INSTALLED
+        OUTPUT_QUIET
+        ERROR_QUIET)
+
+    if(NOT TBB_IS_INSTALLED EQUAL 0)
+        message(STATUS "libtbb-dev not found. Installing libtbb-dev...")
+        execute_process(
+            COMMAND sudo apt-get update
+            COMMAND sudo apt-get install -y libtbb-dev
+            RESULT_VARIABLE TBB_INSTALL_RESULT)
+            
+        if(NOT TBB_INSTALL_RESULT EQUAL 0)
+            message(FATAL_ERROR "Failed to install libtbb-dev")
+        endif()
+    else()
+        message(STATUS "libtbb-dev is already installed.")
+    endif()
+endif()
+
+cmake_policy(SET CMP0169 OLD)
+
+include(FetchContent)
+
+FetchContent_Declare(
+    kokkos
+    GIT_REPOSITORY https://github.com/kokkos/kokkos.git
+    GIT_TAG 4.3.01
+)
+
+FetchContent_GetProperties(kokkos)
+if(NOT kokkos_POPULATED)
+    message(STATUS "Kokkos source directory not found. Downloading Kokkos version 4.3.01 ...")
+    FetchContent_Populate(kokkos)
+    set(Kokkos_Source_DIR ${kokkos_SOURCE_DIR})
+endif()
+
+message(STATUS "Kokkos source directory is ${Kokkos_Source_DIR}")
+add_subdirectory(${Kokkos_Source_DIR} ./kokkos)
+#Kokkos_cmake_settings()
+