WIP: Add sidekiq_options memory_killer_memory_growth_kb

What does this MR do?

To whitelist Workers in Gitlab::SidekiqDaemon::MemoryKiller, we introduced two sidekiq_options: memory_killer_memory_growth_kb and memory_killer_max_memory_growth_kb.

They are used to dynamically adjust soft_limit_rss. In Gitlab::SidekiqDaemon::MemoryKiller, if Sidekiq worker RSS is below soft_limit_rss, it is considered safe.

Refer to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/32469#note_214211861.

Conformity

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