SVN_SILENT made messages (.desktop file)
GUI: do not interfere with saved sizes when restoring geometry

restoreGeometry() and restoreState() manipulate sizes and state of certain
widgets, and there are slots connected to signals which these widgets emit
which, in the end, lead to updating the saved state on disk, which is a wrong
thing to do here.

CCBUG: 323715
GUI: fix the maximized state when restoring geometry

This is a workaround for https://bugreports.qt-project.org/browse/QTBUG-30636.

Thanks to Thomas for comments.

BUG: 323715
REVIEW: 112182
Set default imap port when it is missing in config file

Now default imap port will be determinated from configured imap connection
method (TCP, SSL) instead hardcoded value PORT_IMAP. When imap port is not
default and connection method changes port will be changed to one from config
file (or to default if port is missing in config file).

This patch also eliminate using QSettings in ImapPage::updateWidgets()

REVIEW: 112210
Use one QSettings instance which comes from main.cpp

QSettings by default using application and organization name from global
QCoreApplication instance. But when Trojita code is used by another Qt
application (e.g Kontact) then application name in QCoreApplication is
not "trojita".

With this patch there is only one QSettings instance (with correct names)
which is passed to every class which needs access to trojita settings.

REVIEW: 112207