Legacy Connector

Fixes from GT New Horizons on 1.21.1 (since 0.3.3):

• Joining a world no longer fails with "Invalid player data" when a 1.7.10 command's permission check throws while the server sends the command list (WarpTheory). The command is hidden and the list is sent again once the player has joined.
• JourneyMap's minimap works:
  • The minimap's circle or square mask is kept, so the map no longer covers part of the screen. The legacy depth function and depth/colour writes now apply to batched GUI geometry.
  • Entity.addedToChunk reads the real entity, so JourneyMap maps again.
  • The JDK's internal sun.* packages are exported to legacy mods as on Java 8. JourneyMap's tile painter failed silently before, so every tile was blank.
  • The old log4j 2.0-beta9 PatternLayout.createLayout, RandomAccessFileAppender.createAppender and Strings calls are bridged. This removes the false "Forge incompatible" chat message.
• TXLoader folders (config/txloader/load and forceload) are served as resource packs, matching names regardless of case and reading .lang files. This fixes GTNH's untranslated main menu.