Refactor certification view

src/sakia/gui/main_window/toolbar/about_money.ui

src/sakia/gui/main_window/toolbar/controller.py

src/sakia/gui/navigation/controller.py

src/sakia/gui/navigation/identity/__init__.py

src/sakia/gui/navigation/identity/controller.py

src/sakia/gui/navigation/identity/identity.ui

src/sakia/gui/navigation/identity/model.py

src/sakia/gui/navigation/identity/view.py

src/sakia/gui/navigation/txhistory/controller.py

src/sakia/gui/sub/certification/__init__.py

src/sakia/gui/sub/certification/certification.ui

src/sakia/gui/sub/certification/controller.py

src/sakia/gui/sub/certification/model.py

src/sakia/gui/sub/certification/view.py

src/sakia/gui/sub/transfer/controller.py

src/sakia/gui/widgets/context_menu.py