feat(pack): replace FTB Chunks with Open Parties and Claims and Xaero's maps

FTB Chunks is the only mod in the FTB suite that nothing else depends on --
FTB Quests requires FTB Library and FTB Teams only, and ships no claim-chunk
task type -- so it can leave without touching quests. Open Parties and Claims
takes over claims and force-loading, and the Xaero's suite restores the
minimap, world map and waypoints that b0542f9 removed.

The three Xaero's entries are byte-identical to the ones b0542f9 deleted, so
this reverts the map half of that commit rather than integrating anything new.
Xaero's + OPAC is also the pairing both projects document: the world map
displays OPAC claims and lets you claim and forceload from the map screen.

Drops config/ftbchunks-client.snbt and the .packwizignore negation that
shipped it, since the FTB Chunks minimap it enabled no longer exists. Also
keeps authoring/review material and migration scratch out of the pack index.

Server-side follow-up (not shippable, lives in the world save): set
maxPlayerClaimForceloads to 25, point primaryPartySystem at FTB Teams, and
decide claims.forceload.offlineForceload.

config/ftbchunks-client.snbt

@@ -1,16 +0,0 @@
-# Onion MC modpack default.
-#
-# FTB Chunks computes "minimap.enabled" once as !hasOtherMinimapMod() and then
-# persists the result. While Xaero's Minimap was in this pack that resolved to
-# false and was written into players' configs, where it sticks -- removing the
-# other minimap mod later does not re-enable it. Setting it explicitly here
-# turns the FTB Chunks minimap on for everyone, including players whose config
-# was already written with false.
-#
-# Players who want a different value can copy this to
-# <instance>/local/ftbchunks-client.snbt, which is not overwritten on pack update.
-{
-	minimap: {
-		enabled: true
-	}
-}