Added the ability to benchmark on a directory and output to a chart

[ahmadsharif1]

Example run:

python benchmarks/decoders/benchmark_decoders.py --decoders=tcoptions:device=cuda,tcoptions: --bm_video_speed_min_run_seconds=0.1 --bm_video_dir=/tmp/videos1 --plot_path=chart.png

video=/tmp/videos1/853.mp4, decoder=TorchcodecNonCompiled:
[--------------- video=/tmp/videos1/853.mp4 h264 3840x2160, 4.988317s 59.94005593469701fps ---------------]
                                         |  10 seek()+next()  |  1 next()  |  10 next()  |  create()+next()
1 threads: ------------------------------------------------------------------------------------------------
      TorchcodecNonCompiled:device=cuda  |       3236.4       |   380.1    |    442.3    |                 
      TorchcodecNonCompiled              |                    |            |             |       274.6     
      TorchcodecNonCompiled:             |       2017.1       |   259.9    |    344.5    |                 

Times are in milliseconds (ms).

Produces this chart: