add ability to use benchmark.ini file to customize redline tests

[OVI3D0]

Description

Adds a new [redline] section to benchmark.ini along with some default values for redline testing. These are equivalent to the default values originally used in the FeedbackActor, and allow the user to customize various parts of redline testing from the config object rather than using command flags.

The priority for which value to use is:
command flag -> config object values -> default values in the ConfigureFeedbackScaling class.

And the values that can be customized in the config object include:

• The scale_step (how many clients are unpaused per tick)
• The scale_down_percentage (what percentage of clients are scaled down upon an error)
• The sleep_seconds (how long the FeedbackActor chooses to rest before pushing more load on the host)
• The cpu_window_seconds (How long of a window the FeedbackActor takes into account when calculating average CPU load)
• The cpu_check_interval (How often the FeedbackActor queries the datastore to check avg CPU load)

Issues Resolved

#885

Testing

• New functionality includes testing

Running redline tests with/without various values in the config object

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