Implement IndexedDB document auto-save (#422)

* removed all use of document indicies

* -add u64 support for wasm bridge

* fixed rust formating

* Cleaned up FrontendDocumentState in js-messages

* Tiny tweaks from code review

* - moved more of closeDocumentWithConfirmation to rust
- updated serde_wasm_bindgen to add feature flag

* working initial auto save impl

* auto save is a lifetime file

* - cargo fmt
- fixc error message
- move document version constant

* code review round 1

* generate seed for uuid in js when wasm is initialized

* Resolve PR feedback

* Further address PR feedback

* Fix failing test

Co-authored-by: Keavon Chambers <keavon@keavon.com>
Co-authored-by: otdavies <oliver@psyfer.io>

editor/src/frontend/frontend_message_handler.rs

@@ -31,6 +31,8 @@ pub enum FrontendMessage {
 	UpdateRulers { origin: (f64, f64), spacing: f64, interval: f64 },
 	ExportDocument { document: String, name: String },
 	SaveDocument { document: String, name: String },
+	AutoSaveDocument { document: String, details: FrontendDocumentDetails },
+	RemoveAutoSaveDocument { document_id: u64 },
 	OpenDocumentBrowse,
 	UpdateWorkingColors { primary: Color, secondary: Color },
 	SetCanvasZoom { new_zoom: f64 },