sched: Introduce qos scheduler for co-location

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8MF4R


CVE: NA

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In cloud-native hybrid deployment scenarios, online tasks must preempt
offline tasks in a timely and offline tasks can't affect the QoS of online
tasks, so 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.

The value of qos_level can be 0 or -1, default value is 0. If qos_level
is 0, the group is an online group. otherwise it is an offline group.

Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Wenyu Huang <huangwenyu5@huawei.com>