[epic] Redesign "welcome" and "accept_license" test modules using OOP and libyui-rest-api
Currently the welcome and accept_license test modules contain logic for several different products and cases (e.g. License Agreement screen, Product Selection screen).
That makes the test modules hard to maintain, update in case of changes, or increase coverage.
The goal is to split the modules to the separate tests, that will check a single thing (e.g. like it is already done for RAID tests or partitioner warnings).
The split tests should use libyui-rest-api as a library to communicate with the pages, and OOP approach, so the task also require to create the respective Page layer classes.