Add support for custom global state (#111)

* feat: add 'has_main_file' to App struct

* feat: handle custom state from the main.rs file

* feat: update tutorial template with new setup

* fix: apply clippy hints

* feat: add ApplicationState mention to documentation website

* feat: update version to v0.13.0

examples/tutorial/Cargo.toml

@@ -10,4 +10,5 @@ path = ".tuono/main.rs"
 [dependencies]
 tuono_lib = { path = "../../crates/tuono_lib/"}
 serde = { version = "1.0.202", features = ["derive"] }
+reqwest = "0.12.9"
 

examples/tutorial/src/main.rs

@@ -0,0 +1,11 @@
+use reqwest::Client;
+
+#[derive(Clone)]
+pub struct ApplicationState {
+    pub fetch: Client,
+}
+
+pub fn main() -> ApplicationState {
+    let fetch = Client::new();
+    return ApplicationState { fetch };
+}