Improve Localdb functions & Document
- Updated the uploader to support json-formatted data uploading
- Updated the retriever to generating config files following the registered component data
- Resture config files registered in Local DB if the component has been tested
- Create chip config file by copying the default config file, and connectivity config file following the child-parent relationship registered in Local DB if the component has not been tested
- fixed some errors (mostly caused by mis-matching to updated json.hpp)
- Updated the setting script to prepare the default user&site config file
- Added the description in localdb.md