Merge esp8266-rtos-sdk and esp-idf targets (#4958)

This patch bumps esp8266-rtos-sdk to the latest release. This required to
modify the directory structure and the build system to conform to ESP-IDF
Style. Since esp-idf target already supports ESP-IDF Style, the espressif
targets has been merged to eliminate code duplication.
The target application code has been modified from blinking leds to hello
world to be aligned to other targets.

JerryScript-DCO-1.0-Signed-off-by: Roland Takacs roland.takacs@h-lab.eu

.github/workflows/gh-actions.yml

@@ -271,15 +271,25 @@ jobs:
       - run: make -f ./targets/os/riot/Makefile.travis install-noapt
       - run: make -f ./targets/os/riot/Makefile.travis script
 
-  ESP8266_Build_Test:
+  ESP8266_RTOS_SDK_Build_Test:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
         with:
-          python-version: '2.7' # needed due to ESP8266_RTOS_SDK/tools/gen_appbin.py
-      - run: make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis install-noapt
-      - run: make -f ./targets/baremetal-sdk/esp8266-rtos-sdk/Makefile.travis script
+          python-version: '3.8'
+      - run: make -f ./targets/baremetal-sdk/espressif/esp8266-rtos-sdk/Makefile.travis install-noapt
+      - run: make -f ./targets/baremetal-sdk/espressif/esp8266-rtos-sdk/Makefile.travis script
+
+  ESP_IDF_Build_Test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+        with:
+          python-version: '3.8'
+      - run: make -f ./targets/baremetal-sdk/espressif/esp-idf/Makefile.travis install-noapt
+      - run: make -f ./targets/baremetal-sdk/espressif/esp-idf/Makefile.travis script
 
   Notification:
     runs-on: ubuntu-latest