target/espressif: add application tracing functionality over JTAG

This feature allows to transfer arbitrary data between host and
ESP32 via JTAG.

The main use cases:

1- Collecting application specific data
2- Lightweight logging to the host
3- System behaviour analysis with SEGGER SystemView
4- Source code coverage

Signed-off-by: Erhan Kurubas <erhan.kurubas@espressif.com>
Change-Id: I95dee00ac22891fa326915a3fcac3c088cbb2afc
Reviewed-on: https://review.openocd.org/c/openocd/+/7163
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

src/target/espressif/Makefile.am

@@ -8,6 +8,10 @@ noinst_LTLIBRARIES += %D%/libespressif.la
        %D%/esp_xtensa_smp.h \
        %D%/esp_xtensa_semihosting.c \
        %D%/esp_xtensa_semihosting.h \
+       %D%/esp_xtensa_apptrace.c \
+       %D%/esp_xtensa_apptrace.h \
+       %D%/esp32_apptrace.c \
+       %D%/esp32_apptrace.h \
        %D%/esp32.c \
        %D%/esp32s2.c \
        %D%/esp32s3.c \