clippy all codes (#1214)

1. clippy code
2. add fmt and clippy check in ci

easytier/src/common/mod.rs

@@ -140,8 +140,8 @@ pub fn get_machine_id() -> uuid::Uuid {
     )))]
     let gen_mid = None;
 
-    if gen_mid.is_some() {
-        return gen_mid.unwrap();
+    if let Some(mid) = gen_mid {
+        return mid;
     }
 
     let gen_mid = uuid::Uuid::new_v4();