Grain & Halation Improvements

The current halation and grain modules are artifacts from an early alpha release and there are several issues with them: 1. Halation and grain do not belong in the Luminance panel. 2. The modules are not turned off by hold-clicking on the image (before/after) or split screen view 3. Grain uses simplistic texture blending implementation. **What to expect from the update:** Grain will be replaced with a *Film Structure* module that combines new and advanced* film acutance*, *softness* and grain in a single structure emulation tool for incredibly realistic emulsion properties. Halation color will be simulated through color space transform instead of a texture-location dependent effect. This ensures that all non-structural properties of the halation module carry over into 3D LUT exports for greater highlight color consistency between and third party editing/grading apps. These modules will be located somewhere else in the UI under a "Film Material" category with individual presets that emulate real world film stocks from Kodak, Fuji and Agfa.