This code is basically moved from Uranium to here. This is needed to allow for upgrade plug-ins to define their own configuration types.
Contributes to issue CURA-844.
They no longer mention the version number in their function names. I'd rather have named them import/export but that gave a name clash with Python's 'import' keyword.
Contributes to issue CURA-844.
This plug-in does nothing at the moment. It merely says that it is able to upgrade configuration from version 2.1 to 2.2, but then raises exceptions when you actually try to use it. This is by design. I will now implement the functions that do the conversion.
Contributes to issue CURA-844.