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/esp32/test/test_sleep.c

@@ -16,6 +16,7 @@
 #include "soc/soc.h"            // for direct register read macros
 #include "rom/rtc.h"
 #include "esp_newlib.h"
+#include "test_utils.h"
 
 #define ESP_EXT0_WAKEUP_LEVEL_LOW 0
 #define ESP_EXT0_WAKEUP_LEVEL_HIGH 1