common/kb_configuration library

1. zohodesk_portal_kb package
2. documentation
3. common/kb_configuration.dart

zohodesk_portal_kb package

1. Libraries
2. common/kb_configuration
3. model/kb_configuration_model
4. zohodesk_portal_kb
5. zohodesk_portal_kb_method_channel
6. zohodesk_portal_kb_platform_interface