Refactor and modularize AIManager code

Refactored `AIManager.cs` by moving functionalities into `ModelManager`, `CaptureManager`, and `MathClass` for better organization and separation of concerns.

- Moved Direct3D11 related methods to `CaptureManager`.
- Transferred model initialization/loading to `ModelManager`.
- Relocated utility methods to `MathClass`.
- Updated `SystemEvents.DisplaySettingsChanged` to use `CaptureManager`.
- Made `UpdateFOV` method static.
- Updated `DisposeResources` to use `CaptureManager` and `ModelManager`.
- Enhanced `GetClosestPrediction` to utilize `CaptureManager` and `ModelManager`.
- Added `DDI_CPU` ComboBoxItem in `UI.cs`.
- Shifted from `MessageBox` to logging for model loading errors.

Improved code readability, maintainability, and modularity.

Author: TaylorIsBlue