Kiln mobile scrolling issues

[nelsonpecora]

On mobile, scrolling is very difficult because the component-list dragdrop functionality is triggered. We should improve this so the mobile experience is good.

[nelsonpecora]

We should discuss this before updating the dragdrop code

[pfeytser]

Investigate if sortable.js can do tap and hold drag-drop.

[nelsonpecora]

It doesn't really do that automatically, unfortunately

[nelsonpecora]

There are a few workarounds and open pull requests to add a grab delay to dragula, but it doesn't look like it's being actively maintained. We should probably switch libraries rather than trying to hack it in ourselves.

[nelsonpecora]

Investigation is complete. We should switch to sortable.js, and use a 100ms delay (rather than a pixel deadzone) to solve both the clicking-into-things issue and the mobile scrolling issue.