Use git dependency for rend3

[marceline-cramer]

rend3's last crates.io update was nearly two years ago, so I've decided to update rend3 to the latest trunk on its GitHub repository.

This required some refactoring to update to the newest rend3 API. New PRs that use rend3 will have to be up-to-date, ran through CI, and tested after this is merged.

• get the terminal demo to compile
• update the renderer protocol types to the new renderer API
• test that the updated mesh API works (tested locally with dev-gltf)
• make hearth-rend3 acquire surface to fix Nvidia issue (repeat of 680d58e)
• is the routine-node pattern obsolete?

[marceline-cramer]

Decided to switch away from using rend3 altogether in favor of Bevy.