script: Move WebGL DOM interfaces to script/dom/webgl/ (#38995)

Move interfaces defined by the WebGL spec to the `script/dom/webgl/
`module from `script/dom/`.

`script/dom/webgl*.rs` -> `script/dom/webgl/`
`script/dom/webgl_extensions` -> `script/dom/webgl/extensions`
`script/dom/webgl_validations` -> `script/dom/webgl/validations`

Testing: No changes, just a refactoring

Fixes (partially): #38901

Signed-off-by: Andrei Volykhin <volykhin.andrei@huawei.com>
Co-authored-by: Andrei Volykhin <volykhin.andrei@huawei.com>

components/script/dom/webgl/extensions/ext/extblendminmax.rs

@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use canvas_traits::webgl::WebGLVersion;
+use dom_struct::dom_struct;
+
+use super::{WebGLExtension, WebGLExtensionSpec, WebGLExtensions};
+use crate::dom::bindings::reflector::{DomGlobal, Reflector, reflect_dom_object};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::webgl::webglrenderingcontext::WebGLRenderingContext;
+use crate::script_runtime::CanGc;
+
+#[dom_struct]
+pub(crate) struct EXTBlendMinmax {
+    reflector_: Reflector,
+}
+
+impl EXTBlendMinmax {
+    fn new_inherited() -> Self {
+        Self {
+            reflector_: Reflector::new(),
+        }
+    }
+}
+
+impl WebGLExtension for EXTBlendMinmax {
+    type Extension = Self;
+
+    fn new(ctx: &WebGLRenderingContext, can_gc: CanGc) -> DomRoot<Self> {
+        reflect_dom_object(Box::new(Self::new_inherited()), &*ctx.global(), can_gc)
+    }
+
+    fn spec() -> WebGLExtensionSpec {
+        WebGLExtensionSpec::Specific(WebGLVersion::WebGL1)
+    }
+
+    fn is_supported(ext: &WebGLExtensions) -> bool {
+        ext.supports_gl_extension("GL_EXT_blend_minmax")
+    }
+
+    fn enable(ext: &WebGLExtensions) {
+        ext.enable_blend_minmax();
+    }
+
+    fn name() -> &'static str {
+        "EXT_blend_minmax"
+    }
+}