Transfer ownership of redis and rate limiting to scalability

Why is this change being made?

~"group::application performance" is the current owner of Redis and Rate Limiting Framework categories. However, the team is 100% provisioned on GitLab Plus - a way to offer cloud services to self-managed instances and does not have capacity to address any rate limiting framework nor Redis related queries.

groupscalability, as part of SaaS platforms, is closest to the problem of rate limits and is likely the best point-of-contact for inbound concerns. They have also spent a long time working through Redis-related scaling challenges.

The intent of this MR is to reflect groupscalability's ongoing investments in Redis, their direct impact on Rate Limiting, and their capacity to serve as a point of contact for relevant inbound requests.

As a datastore group, ~"group::application performance" will continue to serve as long-term stakeholders for Redis related concerns.

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