Add a feature to hide translated files on the Project tab

Summary:
This patch adds a feature to hide fully translated files and folders on the project tab.
Three ways to do that :
* In the menu bar
* In the "Go" menu
* With shortcut Ctrl+T

FEATURE: 224179

Reviewers: aacid, #localization, ltoscano, shaforostoff, mlaurent, huftis

Reviewed By: aacid, #localization, huftis

Subscribers: adrianchavesfernandez, schwarzer, huftis

Tags: #localization

Differential Revision: https://phabricator.kde.org/D14219