- update cave installer page to use proper "current" directory in download urls
- update edex installer page to use proper links (directory and generic name) for download urls
- update edex installer page to reference proper "20.3.2-1" version
- removed all images that don't apply for v20
- removed several extra files that aren't necessary (in the docs/pdf/ and docs/python/ directories)
- renamed some images that were preserved that had random character names, to something descriptive