Rename the legacy Graphene crate to document-legacy (#899)

* Rename /graphene to /document-legacy

* Update names in code

document-legacy/src/error.rs

@@ -0,0 +1,24 @@
+use super::LayerId;
+use crate::boolean_ops::BooleanOperationError;
+
+/// A set of different errors that can occur when using this crate.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum DocumentError {
+	LayerNotFound(Vec<LayerId>),
+	InvalidPath,
+	IndexOutOfBounds,
+	NotAFolder,
+	NonReorderableSelection,
+	NotAShape,
+	NotText,
+	NotAnImage,
+	NotAnImaginate,
+	InvalidFile(String),
+}
+
+// TODO: change how BooleanOperationErrors are handled
+impl From<BooleanOperationError> for DocumentError {
+	fn from(err: BooleanOperationError) -> Self {
+		DocumentError::InvalidFile(format!("{:?}", err))
+	}
+}