Quest Enemy Placement

[pacampbell]

Added ability to specify automatic or manual placement of enemies.

• Automatic placement just uses the enemies position in the array + the starting_index value (if provided).
  • This is the default strategy if not provided.
• Manual placement requires that every enemy as an additional "index" field, specifying the position in the group.

Checklist:

• [x] The project compiles
• [x] The PR targets develop branch