unity: separate common and IDF specific functionality

New unity component can be used for testing other applications.
Upstream version of Unity is included as a submodule.
Utilities specific to ESP-IDF unit tests (partitions, leak checking
setup/teardown functions, etc) are kept only in unit-test-app.
Kconfig options are added to allow disabling certain Unity features.

components/freertos/test/test_freertos_task_notify.c

@@ -13,6 +13,7 @@
 #include "driver/timer.h"
 #include "esp_ipc.h"
 #include "unity.h"
+#include "test_utils.h"
 
 #define NO_OF_NOTIFS    4
 #define NO_OF_TASKS     2       //Sender and receiver