More tree icons

[tomlin7]

Feature

Currently every folder and file are using same icon. We can use various kinds of icons based on the file extensions.

https://github.com/billyeatcookies/Biscuit/blob/9e9d38bc311c89e4076f0938f53d14023a43789e/biscuit/core/components/views/sidebar/explorer/directorytree.py#L140

If Icons are base64, they can be loaded on editor startup here

https://github.com/billyeatcookies/Biscuit/blob/9e9d38bc311c89e4076f0938f53d14023a43789e/biscuit/core/settings/styles.py#L107