Refactor font loading from per-document to the portfolio (#659)

* Cleanup default font loading

* Refactor fonts

* Fix menulist mouse navigation

* Format

* Formatting

* Move default font into consts.rs

Co-authored-by: Keavon Chambers <keavon@keavon.com>

graphene/src/operation.rs

@@ -55,7 +55,6 @@ pub enum Operation {
 		size: f64,
 		font_name: String,
 		font_style: String,
-		font_file: Option<String>,
 	},
 	AddImage {
 		path: Vec<LayerId>,
@@ -126,7 +125,6 @@ pub enum Operation {
 		path: Vec<LayerId>,
 		font_family: String,
 		font_style: String,
-		font_file: Option<String>,
 		size: f64,
 	},
 	RenameLayer {