test: Use insta, closes #57

Use insta for UI tests, adds snapshots of UI layout

src/app_data/container_state.rs

@@ -35,7 +35,8 @@ impl ContainerId {
     }
 
     /// Only return first 8 chars of id, is usually more than enough for uniqueness
-    /// TODO container id is a hex string, so can assume that 0..=8 will always return a 8 char ascii &str - need to update tests to use real ids, or atleast strings of the correct-ish length
+    /// TODO container id is a hex string, so can assume that 0..=8 will always return a 8 char ascii &str
+	/// need to update tests to use real ids, or atleast strings of the correct-ish length
     pub fn get_short(&self) -> String {
         self.0.chars().take(8).collect::<String>()
     }