`Bordered` interface

[Sparky983]

Represents something with a border.

Bordered:

• border(Border) -> Set<Border>

Bordered.Builder

• border(Border, Button) -> Bordered.Builder
• border(Set<Border>, Button) -> Bordered.Builder

[Sparky983]

Should we instead be exploring less ad-hoc ways of setting multiple slots?

A quick and simple approach would be:

interface {
  slots(Slots slots, Button button) {
    for (var slot : slots.for(gui)) {
      slot(slot, button)
    }
  }
}

interface Slots {
  Iterable<Slot> for(Gui gui);
}

Gui gui = Gui.chest()
    .rows(6)
    .build()
    .slots(Slots.TOP, Button.of(ItemType.GRAY_STAINED_GLASS_PANE))
    .slots(Slots.EMPTY, Button.of(ItemType.DIAMOND))
    .slots(Slots.column(1), Button.of(ItemType.EMERALD))
    .slots(Slots.rows(4, 5), Button.of(ItemType.GOLD_INGOT));