Update to Svelte 5 with runes

[TeyKey1]

This is a WIP PR aiming to update svelte-konva to Svelte 5 and the new Svelte runes. Currently based on the Svelte 5 preview releases.

svelte-konva aims to be compatible with Svelte 5's runes-only mode, to allow all dependents to use runes-only mode if desired.

Svelte 5 WIP docs: https://svelte-5-preview.vercel.app/docs
Svelte 5 Runes: https://svelte.dev/blog/runes

TODO:

• Make sure the basic examples in the svelte-konva examples work as expected
• Update svelte-konva TS docs if needed
• Create a migration guide for svelte-konva if needed
• Update konva.org docs if needed
• Update konva.org doc examples
• Test for performance differences between the current and new version of svelte-konva

Known issues:

• The component config is not reactive when bound with staticConfig != true. The config data updates correctly, but any reactive statements depending on config do not trigger
• Stage handle cannot be exported as const prop due to being initialized once the wrapper div is rendered (Needs a solution possibly using stores)
• Tests currently do not work due to testing-library being on Svelte 4
• Figure out a way to split the konvaEvents from restProps in the Stage Component (otherwise konva event hooks might also be called on div events)
• Tests not passing
• Some CSS layout issues on the examples webpage (Canvas clipping into source code view)
• $effect is not deeply reactive leading to unreactive config changes in svelte-konva components
• config props are not typed (eg. any) after library build
• Split config prop into its properties -> Allows for fine-grained reactivity and a lot more efficiency in the svelte-konva code