feat: generate project from esp-idf-template.

src/main.rs

@@ -0,0 +1,9 @@
+use esp_idf_sys as _; // If using the `binstart` feature of `esp-idf-sys`, always keep this module imported
+
+fn main() {
+    // Temporary. Will disappear once ESP-IDF 4.4 is released, but for now it is necessary to call this function once,
+    // or else some patches to the runtime implemented by esp-idf-sys might not link properly.
+    esp_idf_sys::link_patches();
+
+    println!("Hello, world!");
+}