Add new support for Workers AI API endpoint (#249)

This adds support for the execute model endpoint, as described here:
https://developers.cloudflare.com/api/resources/ai/methods/run/

This also adds an optional feature `ndarray` that can deserialize
embeddings directly into an `ndarray::ArrayD`.

Author: GodTamIt

cloudflare/Cargo.toml

@@ -14,6 +14,7 @@ default = ["default-tls"]
 blocking = ["reqwest/blocking"]
 default-tls = ["reqwest/default-tls"]
 rustls-tls = ["reqwest/rustls-tls"]
+ndarray = ["dep:ndarray"]
 spec = []
 
 [dependencies]
@@ -25,6 +26,7 @@ chrono = { version = "0.4", default-features = false, features = [
 ] }
 http = "1"
 mockito = { version = "0.31", optional = true }
+ndarray = { version = "0.16", optional = true, features = ["serde"] }
 percent-encoding = "2.1.0"
 reqwest = { version = "0.12.12", default-features = false, features = ["json"] }
 serde = { version = "1.0", features = ["derive"] }