tsk-45: Identify type of Song (#48)

Closes #45

Reviewed-on: phoenix/icarus_meta#48
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

src/detection/mod.rs

@@ -1 +1,8 @@
 pub mod coverart;
+pub mod song;
+
+#[derive(Debug, Default)]
+pub struct FileType {
+    pub mime: String,
+    pub file_type: String,
+}