network: complete ConnectionSession/Save()
network: update test code
network: add newWireedConnectionData()
network: refactor code, rename getConnectionData() to getConnectionDataKey(), etc
network: add remover for each key in ConnectionData
network: add general getter for each field
network: add general setter for each field
network: add comment document for nm setting connection
network: refactor code, get available keys, getSettingIp4ConfigAvailableKeys(), etc