* Replace the many-shapes icon with a new simple download icon svg and update its consumers
* New start and finish animations using svg filmstrip images
* Toolbarbutton progress "bar" is a pie-chart, using a conic-gradient and a variable updated from js
* Show toolbarbutton animations even when download panel is open
Differential Revision: https://phabricator.services.mozilla.com/D113204
03c240126f