chore: Add crate licenses. (#4158)

- GPUI and all dependencies: Apache 2
- Everything else: AGPL

Here's a script that I've generated for it:
https://gist.github.com/osiewicz/6afdd6626e517da24a2092807e6f0b6e

Release Notes:
- N/A

---------

Co-authored-by: David <david@zed.dev>

crates/node_runtime/Cargo.toml

@@ -3,6 +3,8 @@ name = "node_runtime"
 version = "0.1.0"
 edition = "2021"
 publish = false
+license = "AGPL-3.0-only"
+license-file = "../../LICENSE-AGPL"
 
 [lib]
 path = "src/node_runtime.rs"

crates/node_runtime/LICENSE-AGPL

@@ -0,0 +1 @@
+../../LICENSE-AGPL