Switch to Bundle and DMG Images

This release converts plain keyboard layout file to an Ukelele Bundle format. It allows to specify more detailed metadata information along with a correct country flag.

Preferred installer method is now prebuilt DMG-file which does not require manually locating the Keyboard Layouts folder. New layout will be installed to all users by default.

To distinguish the original Estonian layout from the custom one, the layout is now named to Estonian - Nordic referring to the physical Nordic keyboard that majority of MacBooks in Estonia are sold with.