Remove all QtNetwork

src/sakia/core/registry/identities.py

-from PyQt5.QtNetwork import QNetworkReply, QNetworkRequest
 from ucoinpy.api import bma
 from .identity import Identity, LocalState, BlockchainState
 

src/sakia/tests/functional/main_window/test_main_window_dialogs.py

 import unittest
-import asyncio
-import quamash
 from PyQt5.QtWidgets import QDialog, QFileDialog
 from PyQt5.QtCore import QLocale, QTimer
-from PyQt5.QtNetwork import QNetworkAccessManager
 from sakia.gui.mainwindow import MainWindow
 from sakia.core.app import Application
 from sakia.tests import QuamashTest