Actions: Refresh send, clear, save icons

Changed
- document-save (from upstream, uses new "document action" style)
- edit-clear (colorized, easier to see in dark themes)
- send-to (colorized, easier to see in dark themes)
          (use purple which already used for other send/share icons)

Updated
- Borders of many document action icons made semi-transparent, sharper on dark themes
- "Play" icon resized a bit to look more centered, match size of "Stop" icon better