Improvements to Overview Resampling

[wildintellect]

• Switch to rio-cogeo instead of gdal, more python. rio-cogeo info is easier to read
• Make env setup easier outside of MAAP
• Make sure sample data is accessible
• Clean up code comments
• Combine Plots into 1 big plot so it can be exported (PNG/PDF) - number of methods is known but not overviews before reading files.