Build: Convert app directory to modern cmake

update app cmake files. Update header includes where include paths have
changed. Add support for secure test only enablement.

WARNING: This change will not build in isolation, it requires _all_
other cmake changes to successfully build. It is split out only for ease
of understanding.

Signed-off-by: Raef Coles <raef.coles@arm.com>
Change-Id: I3e8eb83c13b5e4dbb428615ba83567f14000285b
diff --git a/app/tfm_integ_test.c b/app/tfm_integ_test.c
index 32cb674..041e733 100644
--- a/app/tfm_integ_test.c
+++ b/app/tfm_integ_test.c
@@ -8,12 +8,11 @@
 #include "tfm_integ_test.h"
 
 #ifdef TEST_FRAMEWORK_NS
-#include "test/framework/test_framework_integ_test.h"
+#include "test_framework_integ_test.h"
 #endif
 
 #ifdef TEST_FRAMEWORK_S
-#include \
-  "test/test_services/tfm_secure_client_service/tfm_secure_client_service_api.h"
+#include "tfm_secure_client_service_api.h"
 #endif
 
 #if defined(TEST_FRAMEWORK_NS) || defined(TEST_FRAMEWORK_S)