New Shortcut names and Ui

Based on this discussion, it seems thers is a general support for new naming of Shortcuts.
https://musescore.org/en/node/278864

As proposed by @harbinger the shortcuts should be organise by functional categories and cosistent naming scheme.

Based on this a new version of Preferences/Shortcuts has been made, that will take Category and Name and present them together.
Additionally filters have been added so the list can be filtered on four criteria:
Category , Group (e.g. standard,user,undefined) /search on name/search on shortcut

The existing Description has been retained in order to provide a translated text until the new shortcut names has been fully translated.

Categories and the new names will be added to the initialiser list in shortcut.cpp

Also the print facility has been revised so it print only the active shortcuts, and organised by category.
An action getAction("print-shortcuts") has been defined and added to the Help menu.
The print method is defined as museScore::printShortcuts, and placed in shortcut.cpp.

Preferences screeen and a sample printout is attached.