Add basic dlsite crawler

Reformat application config

src/config/mod.rs

@@ -7,6 +7,14 @@ use serde_json;
 pub mod types;
 
 impl ApplicationConfig {
+    pub fn get_config() -> Result<Self> {
+        if APP_CONIFG_FILE_PATH.exists() {
+            ApplicationConfig::from_file(&APP_CONIFG_FILE_PATH)
+        } else {
+            Ok(ApplicationConfig::new())
+        }
+    }
+
     pub fn from_file(path: &PathBuf) -> Result<Self> {
         let reader = std::fs::File::open(path)?;
         let result = serde_json::from_reader(reader)?;