This PR implements support for loading and displaying images from a
local file using gpui's `img` element.
API Changes:
- Changed `SharedUrl` to `SharedUrl::File`, `SharedUrl::Network`
Usage:
```rust
// load from network
img(SharedUrl::network(...)) // previously img(SharedUrl(...)
// load from filesystem
img(SharedUrl::file(...))
```
This will be useful when implementing markdown image support, because we
need to be able to render images from the filesystem (relative/absolute
path), e.g. when implementing markdown preview #5064.
I also added an example `image` to the gpui crate, let me know if this
is useful. Showcase:
<img width="872" alt="image"
src="https://github.com/zed-industries/zed/assets/53836821/b4310a26-db81-44fa-9a7b-61e7d0ad4349">
**Note**: The example is fetching images from [Lorem
Picsum](https://picsum.photos) ([Github
Repo](https://github.com/DMarby/picsum-photos)), which is a free
resource for fetching images in a specific size. Please let me know if
you're okay with using this in the example.
