Prep gcore splitup: move various symbols into their own modules (#2746)

* move `trait AsU32` from `gcore::vector::misc` to `gcore`

* move blending and gradient to their own modules

* fix unused warnings

* move `Quad`, `Rect` and `BBox` to `gcore::math`

* extract `ReferencePoint` and transform nodes from `transform`

* move color-related code to `mod color`

* fix unused warning in test code

* move blending-related nodes and code to `mod blending_nodes`

* move ClickTarget code to `mod vector::click_target`

editor/src/messages/tool/common_functionality/shapes/shape_utility.rs

@@ -13,7 +13,7 @@ use bezier_rs::Subpath;
 use glam::{DAffine2, DMat2, DVec2};
 use graph_craft::document::NodeInput;
 use graph_craft::document::value::TaggedValue;
-use graphene_std::renderer::ClickTargetType;
+use graphene_std::vector::click_target::ClickTargetType;
 use graphene_std::vector::misc::dvec2_to_point;
 use kurbo::{BezPath, PathEl, Shape};
 use std::collections::VecDeque;

editor/src/messages/tool/common_functionality/snapping/layer_snapper.rs

@@ -5,6 +5,7 @@ use crate::messages::portfolio::document::utility_types::misc::*;
 use crate::messages::prelude::*;
 use bezier_rs::{Bezier, Identifier, Subpath, TValue};
 use glam::{DAffine2, DVec2};
+use graphene_std::math::math_ext::QuadExt;
 use graphene_std::renderer::Quad;
 use graphene_std::vector::PointId;