[fuel-mirror] need to drop logic for filtering input data

[Bulat Gaifullin]

The fuel-mirror has option -G | --group, that allows specify the repository groups that needs to process.
This option is violation of data-driven concept, need to rework functional to drop it.

In current implementation this option is used to avoid duplication of data in input files.
At first need to drop the dependencies between repositories, this will help to make the code simpler and drop this option.