reimplement sortable drag'n'drop cards component for admin view

[elioqoshi]

Currently the implementation of the sortable drag'n'drop cards component is done from scratch and doesn't work very smoothly and intuitively. We should reimplement the component with something along the lines of the Grid component here:

http://clauderic.github.io/react-sortable-hoc/#/basic-configuration/grid?_k=3cu5am

This is only available in the admin view obviously.

[kominoshja]

This has some problems on implementation and needs more time. Removing milestone.

[kominoshja]

Maybe this works? @albanafmeti
http://cheton.github.io/react-sortable/

[albanafmeti]

@elioqoshi needs to confirm if that's fine.

[elioqoshi]

No, that looks almost worse than what we have right now.

[keunes]

For me (end user with very limited tech background), drag-n-drop looks & works nice, when it works. I wouldn't necessarily change the 'how' but rather the stability: sometimes I can't use drag-n-drop anymore after using it once. Refreshing the page will re-enable it.

[Edit] Also (not sure if it should get its own ticket), drag-n-drop of sections would be a welcome addition.