feat(chromium): add support for emulated media features in Chromium (#1474)

Closes https://github.com/gotenberg/gotenberg/issues/1460

It can be easier to print a "clean" PDF of some pages if you emulate
media features like `prefers-reduced-motion`. Add support for that
emulation.

pkg/modules/chromium/chromium.go

@@ -165,11 +165,28 @@ type Options struct {
 	// "print".
 	EmulatedMediaType string
 
+	// EmulatedMediaFeatures are the media features to emulate, e.g.,
+	// [{"name": "prefers-color-scheme", "value": "dark"}].
+	EmulatedMediaFeatures []EmulatedMediaFeature
+
 	// OmitBackground hides the default white background and allows generating
 	// PDFs with transparency.
 	OmitBackground bool
 }
 
+// EmulatedMediaFeature gathers the available entries for emulating a media
+// feature.
+type EmulatedMediaFeature struct {
+	// Name is the media feature name (e.g., "prefers-color-scheme",
+	// "prefers-reduced-motion").
+	// Required.
+	Name string `json:"name"`
+
+	// Value is the media feature value (e.g., "dark", "reduce").
+	// Required.
+	Value string `json:"value"`
+}
+
 // DefaultOptions returns the default values for Options.
 func DefaultOptions() Options {
 	return Options{
@@ -187,6 +204,7 @@ func DefaultOptions() Options {
 		UserAgent:                       "",
 		ExtraHttpHeaders:                nil,
 		EmulatedMediaType:               "",
+		EmulatedMediaFeatures:           nil,
 		OmitBackground:                  false,
 	}
 }