sched: Introduce qos scheduler for co-location

hulk inclusion
category: feature
bugzilla: 51828, https://gitee.com/openeuler/kernel/issues/I4K96G


CVE: NA

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We introduce the idea of qos level to scheduler, which now is
supported with different scheduler policies. The qos scheduler
will change the policy of correlative tasks when the qos level
of a task group is modified with cpu.qos_level cpu cgroup file.
In this way we are able to satisfy different needs of tasks in
different qos levels.

Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Zheng Zucheng <zhengzucheng@huawei.com>
Reviewed-by: Chen Hui <judy.chenhui@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>