Adds a new UI panel, the Status Bar, which replaces current contextmenu menu. <perspective-statusbar>, the Custom Element which implements this feature, is written in Rust and lives in the confusingly-named @finos/perspective-vieux package, which will someday replace @finos/perspective-viewer. For now though, it is inlined similarly so @finos/perspective-cpp package, so as not to pollute the project's NPM module namespace. Structurally, this package is very similar to the other Custom Elements packages in Perspective; there is a static HTML template which is render to the Shadow DOM at element instantiation, and small JavaScript API:

• set_table() takes the Perspective Table() object for this viewer.
• set_view() takes the associated View(), must be called after set_table() but can be called multiple times.
• The element dispatches the perspective-statusbar-reset non-bubbling event when the reset button is clicked.

In order to bind to the customElements.register() method, a short shim of the JavaScript-accessible methods and class structure lives in src/js/boostrap.js; this is possible to do in Rust also, but wasm-bindgen does not (seem to?) have native ES6 class binders, which makes this a bit hacky. Within Rust is

• The StatusBarElement struct and methods, from which the JavaScript API dispatches.
• The download and copy modules, which re-create and replace this functionality from @finos/perspective-viewer.
• Simple binders for Perspective's JavaScript API into Rust (which mirrors what a hypothetical native Rust API would look like fairly closely).
• Some utility methods to wrap the typed-html package a renderer and extractor.
• Simple utility methods to turn various flavors of Rust async/fn types into JavaScript Closure types that do not leak.
• Unit and integraiton tests using wasm-bindgen's headless support.