SM64: Configurable Camera Volume/ZoomOut Mask export paths

[someone2639]

Preparation for HackerN64/HackerSM64#827 which aims to split out camera related data into separate files for readability. Instead of hardcoding camera.c, we now have two fast64.json configurable paths to point the level writer to the correct export files (including the ability to have a specific file depending on the level_name param). This allows us to cut another 281 lines from the main camera.c.

Testing

• Manual export works in a HackerSM64 3.0 repo with PR 827
  • And still works if we export to a level without an existing trigger file (like Whomp's Fortress)
• Manual export doesn't break in any older HackerSM64
  • or Vanilla
• Loading a repo without these new settings will set them back to default automatically
  • having a default that you can reset via normal blender GUI should be fine in this case? It would definitely be ideal if it was auto set but seems like a non trivial change
• Completely custom level names still work
  • in Vanilla too