check-kernel-fix: check for config value inconsistencies in branch hierarchies
    
    Currently the tool doesn't report a eligible branch because a related config
    is disabled in one of the parents. We have cases where config is enabled in a
    child, but disabled in parent. For example: CONFIG_AX25 is enabled in
    SLE15-SP3-LTSS, but disabled in it's parent cve/linux-5.3-LTSS.
    Report such anomalies and handle this corner case.
    
    Also introduce two new branch states nope_unaffected_config and
    unknown_config_disagree. Former indicates that branch has config
    disabled, while latter indicates that config value is inconsistent with
    one or more of it's children branches.