BWE Simulation Framework: Standard plot logging

-- Made plot logging from MetricRecorder and from RateCounterFilter/PacketReceiver standard to fit python and shell plotting scripts likewise.

-- RateCounterFilter is initialized with algorithm name.
-- Removed spare commas and duplicated flow ids from RateCounterFilter name.
-- Added optional plot_delay and plot_loss in MetricRecorder.
-- PacketReceiver can plot directly plot delay if there is no metric_recorder_.
-- Added comments to plot scripts.

R=stefan@webrtc.org

Review URL: https://codereview.webrtc.org/1253473004 .

Cr-Commit-Position: refs/heads/master@{#9636}
14 files changed