feat!: add function calling support to client.chat() & client.chat_async()

BREAKING CHANGE: Too many to count in this version. Check the README examples.

examples/embeddings.rs

@@ -0,0 +1,17 @@
+use mistralai_client::v1::{client::Client, constants::EmbedModel};
+
+fn main() {
+    // This example suppose you have set the `MISTRAL_API_KEY` environment variable.
+    let client: Client = Client::new(None, None, None, None).unwrap();
+
+    let model = EmbedModel::MistralEmbed;
+    let input = vec!["Embed this sentence.", "As well as this one."]
+        .iter()
+        .map(|s| s.to_string())
+        .collect();
+    let options = None;
+
+    let response = client.embeddings(model, input, options).unwrap();
+    println!("First Embedding: {:?}", response.data[0]);
+    // => "First Embedding: {...}"
+}