[FEATURE ADD] Add progress save state file

[HunterAP23]

Describe the feature that is being tested/implemented
Add file to record the state of the program in case the program was closed before all tasks were completed.

• Add save state functionality to encoder module
  • Save state file should record what video encodes were not started, completed, or cancelled/stopped.
  • For cancelled/stopped encodes, make sure the output file does not exist, and if so delete it before reattempting the encode.
• Add save state functionality to VMAF calculations
  • Save state file should record what VMAF calculations were not started, completed, or cancelled/stopped.
  • For cancelled/stopped calculations, make sure the output report file does not exist, and if so delete it before reattempting the calculation
• Add save state functionality to VMAF plotter
  • Save state file should record what VMAF plotting were not started, completed, or cancelled/stopped.
  • For cancelled/stopped plots, make sure the output graph photo and video files do not exist, and if so delete it before reattempting the plotting

List any relations to other issues in this repository or in other repositories
N/A