add requirements for parseCSS and remove CoVex stuff from repo

netex/assets/styles/images/color.png

netex/assets/styles/images/hue.png

netex/assets/styles/images/line.gif

netex/assets/styles/images/loading.gif

netex/assets/styles/images/password-meter.png

netex/assets/styles/primeicons.css

netex/assets/styles/primeng.min.css

netex/assets/styles/theme.css

netex/assets/uniprot.png

netex/assets/virus.png

netex/assets/virus_background.jpg

netex/assets/virus_background.png

netex/assets/virus_backgroundr.jpg

package.json

prefixCSS.py

requirements.txt