First attempt at a GPU runner

Currently failing with an error I don't understand:

```
wgpu error: Validation Error

Caused by:
  In Device::create_shader_module, label = '...\image_binary.spv'

Shader '...\image_binary.spv' parsing error: InvalidTypeWidth(1)
```

examples/image-runner/build.rs

@@ -0,0 +1,28 @@
+use cargo_gpu_install::install::Install;
+use cargo_gpu_install::spirv_builder::{Capability, ShaderPanicStrategy, SpirvMetadata};
+use std::path::PathBuf;
+
+pub fn main() -> anyhow::Result<()> {
+    let manifest_dir = env!("CARGO_MANIFEST_DIR");
+    let crate_path = [manifest_dir, "..", "image-binary"]
+        .iter()
+        .copied()
+        .collect::<PathBuf>();
+
+    let install = Install::from_shader_crate(crate_path.clone())
+        .within_build_script()
+        .run()?;
+    let mut builder = install.to_spirv_builder(crate_path, "spirv-unknown-vulkan1.3");
+    builder.build_script.defaults = true;
+    builder.shader_panic_strategy = ShaderPanicStrategy::SilentExit;
+    builder.spirv_metadata = SpirvMetadata::Full;
+    builder.capabilities = vec![Capability::Int8, Capability::Int16, Capability::Int64];
+
+    let compile_result = builder.build()?;
+    let spv_path = compile_result.module.unwrap_single();
+    println!(
+        "cargo::rustc-env=SHADER_SPV_PATH_IMAGE_BINARY={}",
+        spv_path.display()
+    );
+    Ok(())
+}