Import app manager, samples and test-tools

core/app-mgr/app-manager/coding_rule.txt

@@ -0,0 +1,15 @@
+Coding rules:
+
+1. module implementation can include the export head files of associated runtime
+
+2. app manager only call access the module implementation through the interface API
+
+3. module implementation can call the app manager API from following files:
+   - util.c
+   - message.c
+   
+4. platform API: To define it   
+   
+5. Any platform dependent implementation of app manager should be implemented in the 
+   platform specific source file, such as app_mgr_zephyr.c   
+