Worlds: more worlds, portals and resets

New in 0.3, module worlds, off by default; with nothing in worlds it touches nothing. Keep the main world beautiful and do the digging somewhere else.

One line per world in worlds.worlds, parts key=value separated by |:

id=myserver:mining | name=Mining world | template=amplified | seed=random | reset=first monday 05:00 | homes=false | warp=mine

• template: normal, amplified, large-biomes, floating-islands, caves, ore-world, flat, void, arena, nether, end, or existing (only rules, for the overworld, the Nether or a mod's world).
• seed: same-as-main, random (new at every reset) or fixed:<number>.
• reset: off, first monday 05:00, monthly 1 05:00, weekly sunday 04:00, every 14d; read in time-zone.
• Spawn: spawn=x,y,z, spawn-radius (6), spawn-depth (12), spawn-height (8); platform=true builds a platform safe from lava in a roofed world, with the signs in platform-signs.
• Rules: homes, claims, force-load (true/false), pvp=default|off, keep-inventory=default|true, banned-blocks=a:b,c:d (placing refused), border=<blocks>.
• More: ores=off|normal|dense|rich|<veins> (extra veins from every ore the pack tags, weighted by ore-weights, mods' ores included), warn=7d,1d,1h,10m, welcome=<text>, warp=<name> (a warp to the spawn, made once), replaces=<datapack folder> (take over a world an older datapack made).

A world is a dimension file in Keystone's own datapack (<world>/datapacks/keystone-worlds); the game reads it at its next start, so a new world needs one restart and then lives on. Removing Keystone leaves the worlds as they are.

A reset happens while the server is down: when it stops on or after the planned moment (up to ten minutes early still counts, so a daily restart at that hour does it), the spawn area is saved; the next start wipes the world before the game opens it, pastes the spawn back exactly, releases claims and force-loads in it and forgets homes there. Nobody is ever inside, and nothing is half-saved. Players are warned at warn times in game and, with discord-channel, on Discord. A player who comes back from before a reset is taken to the spawn.

/keystone worlds reset <world> then confirm (or cancel) asks for a reset at the next stop (keystone.worlds.reset); POST /v1/worlds/reset (scope operations.run) does the same. /keystone worlds spawn <world> takes you there.

worlds.portals, a line each: name=mine | world=minecraft:overworld | from=10,64,10 | to=12,67,10 | target=myserver:mining. Step into the box, arrive in the target world (its spawn, or world@x,y,z[,yaw]); permission=<node> limits who may use it. Build the frame yourself; /keystone worlds portal <name> corner and … to <target> write the line from where you stand, … remove takes it away (keystone.worlds.portal).

GET /v1/worlds (scope status.read) lists the worlds, their next reset and their rules.