Kanban pad on the new Graph ECHO

[rzadp]

• Data retrieved by select() is lagging behind (first new item shows up only after second one is created)
  • Note: resolved by heavily modyfing useSelection hook from echo-demo
• Labels as a native set in ObjectModel. Requires dxos-deprecated/echo#398
• Links between cards and lists, as native links in db instead of hacked property links

To work out

• Extract useSelection - copied from echo-demo for now
• Can links be "moved" atomically? (Delete one link and create new one in one go? It would be needed for moving cards between lists)
  • Note: looks like there is no API neither to remove links or to change (re-link) them?