Server Model Allocation (Part 1): Refactor entity datasets and handlings into external configs

[MohabCodeX]

Summary

Moves hardcoded server entity data and vehicle handlings from C++ into separate .conf files.

This is Part 1 of adding custom model allocation to the server. Follow-up PRs will add the model manager, dynamic ID allocation, and server-side Lua functions.

Note on diff size: The large line count is only because objects.conf contains 14,000 lines of object IDs, and we deleted 7,500 lines of hardcoded handling arrays from CHandlingManager.cpp. The actual C++ code changes are very small (~350 lines).

Changes

• Added config files in mods/deathmatch/:
  • objects.conf (14,339 lines)
  • peds.conf (299 lines)
  • vehicles.conf (214 lines)
  • handling.conf (213 lines)
• Added loader classes for handling, vehicles, objects, and peds.
• Removed 7,554 lines of hardcoded handling data from CHandlingManager.cpp.

Next Steps

• Part 1 (This PR): Config files and loaders.
• Part 2: Server CModelManager and dynamic ID allocation.
• Part 3: Server-side Lua functions.
• Part 4: Sync and packet updates.

Test Plan

1. Start the server.
2. Run via runcode:

   srun h = getOriginalHandling(411); outputChatBox("Infernus Mass: " .. tostring(h.mass))