refactor: move business logic into app

* also move all at directory root crate

* all actors are into lib directory

* formatter is into system_monitor now

src/main.rs

@@ -0,0 +1,25 @@
+use discord_client::DiscordNotifier;
+use dotenvy::dotenv;
+use system_monitor::SystemMonitor;
+
+mod app {
+    pub mod service;
+}
+
+fn main() {
+    dotenv().ok();
+
+    let notifier = DiscordNotifier::new(
+        std::env::var("DISCORD_WEBHOOK").expect("DISCORD_WEBHOOK environment variable not set"),
+        "System Monitor".to_string(),
+        "https://cdn.shopify.com/s/files/1/0262/1423/6212/files/Lord_of_the_Rings_eye_of_Sauron_-_Ghtic.com_-_Blog.png?v=1579680018".to_string(),
+    );
+
+    let monitor =
+        SystemMonitor::new(system_monitor::resource_threshold::get_default_resource_thresholds());
+
+    let formatter = system_monitor::alert_formatter::AlertFormatter;
+
+    let service = app::service::new(notifier, monitor, formatter);
+    service.run();
+}