Experimentally add a headless mode

[maxammann]

Here is an example of wgpu in headless-mode: https://github.com/gfx-rs/wgpu/tree/master/wgpu/examples/capture

Fix_es: #47

💻 Examples

🚨 Test instructions

✔️ PR Todo

• Included links to related issues/PRs

[Drabble]

Nice work!

I think we should consider making this headless mode executable through the src/bin directory. It could be useful to run the headless mode with a command like cargo run --bin headless.

With Binaries we can install the binary directly with cargo install. Cargo install docs are here and here.

[maxammann]

Closing this now as it only was an experiment. Code changed now after #63