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>

graphene/src/consts.rs

@@ -1,5 +1,8 @@
 use crate::color::Color;
 
+// Document
+pub const GRAPHENE_DOCUMENT_VERSION: &'static str = "0.0.1";
+
 // RENDERING
 pub const LAYER_OUTLINE_STROKE_COLOR: Color = Color::BLACK;
 pub const LAYER_OUTLINE_STROKE_WIDTH: f32 = 1.;