Intention to update jaxb-api to major version 4

[Marián Konček]

I am planning to update jaxb-api to version 2 along with updating jaxb-* 
packages. The package's classes use a different namespace "jakarta" 
instead of "javax".

I am also planning to add a compatibility package jaxb-api2. 
Nevertheless, dependent packages may need to change their BuildRequires.

-- 
Marián Konček