Create JsonConfigLoader.

This CL adds a JsonConfigLoader to parse the vehicle proeprty
config file in JSON format.

This CL also adds DefaultConfigTest to verify the JSON file
is compatible with the existing header file.

Test: atest JsonConfigLoaderUnitTest
atest VehicleHalDefaultConfigTest
Bug: 238685398

Change-Id: If679afd2245cb7e2a49fd964f343b660c9bcea25
diff --git a/automotive/vehicle/TEST_MAPPING b/automotive/vehicle/TEST_MAPPING
index fa0b791..da8416c 100644
--- a/automotive/vehicle/TEST_MAPPING
+++ b/automotive/vehicle/TEST_MAPPING
@@ -7,6 +7,15 @@
       "name": "VehicleHalDefaultConfigTest"
     },
     {
+      "name": "VehicleHalDefaultConfigTestEnableTestProperties"
+    },
+    {
+      "name": "JsonConfigLoaderUnitTest"
+    },
+    {
+      "name": "JsonConfigLoaderUnitTestEnableTestProperties"
+    },
+    {
       "name": "VehicleHalVehicleUtilsTest"
     },
     {