This PR refactors the `studio` project's entry-point functions for
better maintainability and ease of use for local development.
### Overview
* `start_internal` refactored to return a `bevy::app::App` instead of
calling `App::run`, allowing for finer-grained configuration of unique
use cases
* Temporary `start` function added for WASM
* `init` function removed
* `main` standalone entry-point refactored to call `start_internal`
### Fixes
* Crash on non-WASM builds due to missing `StudioMode` resource
* Warning on non-WASM builds due to an unused variable
This commit implements a Sketchfab-style single-object viewer as a minimal
proof-of-concept.
### `@storyteller/studio-web`
This is a new package to house web components for interfacing with the
`@storyteller/studio` WASM library. It currently includes a single component,
`<sts-viewer />`, which is exported from `@storyteller/studio-web/viewer`.
### `react-frontend`
This is a new application intended as a proof-of-concept and testbed for React
interop with `@storyteller/studio-web`.
Web components are currently a little bit fiddly to use in a React application.
`react-frontend/src/app/studio-viewer.tsx` demonstrates how a React-idiomatic
component can be written as a thin wrapper around a web component, and
`react-frontend/src/app/app.tsx` demonstrates that wrapper component in use.
Danny McGee