Add ESP certificate bundle feature

Adds the ESP certificate bundle feature that enables users to bundle a
root certificate bundle together with their application.

Default bundle includes all Mozilla root certificates

Closes IDF-296

examples/protocols/https_x509_bundle/example_test.py

@@ -0,0 +1,40 @@
+import re
+import os
+import sys
+
+try:
+    import IDF
+except ImportError:
+    # this is a test case write with tiny-test-fw.
+    # to run test cases outside tiny-test-fw,
+    # we need to set environment variable `TEST_FW_PATH`,
+    # then get and insert `TEST_FW_PATH` to sys path before import FW module
+    test_fw_path = os.getenv("TEST_FW_PATH")
+    if test_fw_path and test_fw_path not in sys.path:
+        sys.path.insert(0, test_fw_path)
+    import IDF
+
+
+@IDF.idf_example_test(env_tag="Example_WIFI", ignore=True)
+def test_examples_protocol_https_x509_bundle(env, extra_data):
+    """
+    steps: |
+      1. join AP
+      2. connect to multiple URLs
+      3. send http request
+    """
+    dut1 = env.get_dut("https_x509_bundle", "examples/protocols/https_x509_bundle")
+    # check and log bin size
+    binary_file = os.path.join(dut1.app.binary_path, "https_x509_bundle.bin")
+    bin_size = os.path.getsize(binary_file)
+    IDF.log_performance("https_x509_bundle_bin_size", "{}KB".format(bin_size // 1024))
+    IDF.check_performance("https_x509_bundle_bin_size", bin_size // 1024)
+    # start test
+    dut1.start_app()
+    num_URLS = dut1.expect(re.compile(r"Connecting to (\d+) URLs"), timeout=30)
+    dut1.expect(re.compile(r"Connection established to ([\s\S]*)"), timeout=30)
+    dut1.expect("Completed {} connections".format(num_URLS[0]), timeout=60)
+
+
+if __name__ == '__main__':
+    test_examples_protocol_https_x509_bundle()