Revert "Add pixi 2D webgl to project libraries"

This reverts commit 387a5f6ddda594f5f3bdacf6f1f968469ccfac9a.
Hide teaching buttons when resetting or retrying
Move fetch call from sync model to collections
Cleaned up stuff to prepare for better syncing
Updated login binding to match sync changes
Remove box-shadow from modal

In general usual box-shadow on mobile devices seems to cause noticeable
performance issues.
Improve initial download progress flow