Improve animations

[haustraliaer]

• [x] Drawer opening and closing
• [x] Dropdowns opening and closing (max height is slow)
• [x] Fade transition performance on mobile
• [x] Force spinner to finish spinning to a stop position
• [x] Refactor velocity animations to use Forcefeeding

The drawer animation is both a performance issue and a browser support issue. I'd like to find a way of moving the entire drawer & app frame as one element, rather than re-positioning both individually. We should probably also use veloctiy to do this, rather than css transitions.

[haustraliaer]

Related: https://github.com/hivewallet/hive-js/issues/63

[haustraliaer]

Spinner now spins back to start position, rather than jumping as per #160

[haustraliaer]

Draw was too hard to animate as one unit (and not break other things)... it was also less performant with velocity lel.

I've reconfigured it to open to a fixed position / width for later breakpoints though and removed the flexbox code that was causing weird glitching in chrome.

[haustraliaer]

Removed the dropdown code for now as User Details is the only thing left in the drawer after moving tokens to a tab.