feat: 🎸 add $json method to get raw dictionary values

[kaisermann]

✅ Closes some topics brought on #109, #83

• Add a json reactive method that can be used to return a raw value from the dictionary (could be called $raw 🤔 )

// en.json
{
  "list": {
    "items": [{"name": "Name 1"}, {"name": "Name 2"}]
  }
}

<ul>
  {#each $json<Item[]>('list.items') as item}
    <li>{item.name}</li>
  {/each}
</ul>

• Simplified the structure of the browser entrypoint