Add more options for the password displaying

[l3u]

This addresses both issue #586 and issue #577.

I added two additional checkboxes to the configuration dialog:

• "Use a monospace font" that, if activated, sets the system's default monospace font for both the QTextBrowser and all QLineEdits used to display password files
• "Display the files content as-is" that, if activated, skips the parsing of the pass file content and simply puts everything into the QTextBrowser, as pass does when used on the console.

Imo this won't hurt, as the default behavior remains unchanged, but it's convenient for console pass users that want to have the same behavior in QtPass.

[l3u]

Just to say it: I adapted the way you did it, like

void QtPassSettings::setNoLineWrapping(const bool &noLineWrapping) {
  getInstance()->setValue(SettingsConstants::noLineWrapping, noLineWrapping);
}

but in such a case, it's not really meaningful to use a const reference to a bool value. The pointer to the bool value is bigger than the value itself, so it's actually worse than simply passing the variable by value ;-)

But this is another story …