Add Redis::CommandRecorder

What does this MR do and why?

Contributes to #368697 (closed)

Problem

We have tooling to detect N+1 database queries in tests, but we don't have a way to do the same for Redis.

Proposal

Introduce a RedisCommands::Recorder class to record Redis queries and allow to access them.

It's a MVC that only defines basic methods.

How to set up and validate locally

control = RedisCommands::Recorder.new do
  # your code that sends Redis commands
end

# number of all requests
expect(control.count).to eq(5)

# number of all get requests
expect(control.by_command(:get).count).to eq(5)

# use a pattern to fetch only specific keys
control = RedisCommands::Recorder.new(pattern: 'branch_names') do
  # your code that sends Redis commands
end

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.