Migrate build to CMake and standard github workflows

Replace makefiles with CMakeLists.txt. This will allow for IDE and
platform agnostic builds of FFF.

Update the CI for FFF to use github workflows which don't depend on MS VC.
The workflow added will verify the pull requests sent to master buy
running 'buildandtest' which mirrors the developer workflow.

Signed-off-by: Yuval Peress <peress@google.com>

examples/weak_linking/test/src/display.test.c

@@ -0,0 +1,24 @@
+#include "test_common.h"
+#include "display.h"
+
+DEFINE_FFF_GLOBALS;
+
+
+int main(void)
+{
+   init_tests();  // Resets common and hook errors to asserts.
+
+   GLOBAL_TEST_bus_read_ret[2] = 0x10;
+   assert( display_init() == true );
+   assert( bus_read_write_fake.call_count == 1);
+
+   display_update( "TEST INFO" );
+   assert( bus_read_write_fake.call_count == 1 );
+   assert( bus_write_fake.call_count == 1 );
+
+   GLOBAL_TEST_bus_read_ret[2] = 0x00;
+   assert( display_init() == false );
+
+   printf("Test " __FILE__ " ok\n");
+   return 0;
+}