memcg: introduce memcg swap qos feature

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7CGGT


CVE: NA

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Introduce memcg swap qos including subsequent sub-features.
Add CONFIG_MEMCG_SWAP_QOS and static key memcg_swap_qos_key.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>