Add configuration IgnoreFiles for package config files.
So users can rely on this to skip license conflict for
some generated files.
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>