Automate the selection of candidate image widths

[verlok]

Scenario

Currently, the npm run extract command extracts the intrinsic image widths used from the images defined in the config, and provides recommended image sizes for the responsive images that will be generated with npm run start.

The automatic recommendation though works fine only for the smallest mobile phone and not for all the devices in the resolutions.xlsx. There is still a manual process to be done for the selection of the image sizes which are best for all the resolutions.

Acceptance criteria

All the image sizes proposed by the extract algorithm and saved in the chosenImageWidth column of the data/datafile.xslx have a number close to 1.0 for the chosenRTIPixelRatio (chosen rendered-to-ideal-pixel-ratio), so that a few images dimensions are generated and reused across all resolutions.