Open dialogs with the Quick Actions key (G)

• New: quick-action: true puts a dialog on Minecraft's Quick Actions key (G, 1.21.6 and newer). With several dialogs on it, G shows a list to pick from.
• By default G opens the dialog straight away, drawn for each player as they join: their name, head and PlaceholderAPI values show what was true then, until they rejoin. Needs Paper.
• quick-action: launcher has G open a small screen with an Open button that opens the dialog fresh, for dialogs whose values change. Spigot, dialogs with a permission and drawn dialogs always use it. The button's words are messages.quick-open.
• The key is set by a datapack Dialog Engine writes, so adding or removing a dialog takes a server restart. The console says when one is owed.
• Fixed: on a brand-new 26.x world, a datapack written on the first start landed where the server never reads it.