Add support for environment file generation in EnvFile struct

- Introduced new methods for writing environment files in YAML and DotEnv formats.
- Updated EnvFile struct to include a buffer for storing key-value pairs.
- Modified write_env_files function to create and write to environment files based on configuration.
- Added tests for environment file writing functionality.

apps/container/src/util.rs

@@ -29,17 +29,18 @@ pub fn write_env_files(db_config: &DBConfigInfoType) {
         DBConfigInfoType::PreExisting(config) => (config.db_type.clone(), config.url.clone()),
     };
 
-    let api_env_file = EnvFile {
-        file_type: env::EnvFileType::Yaml,
-        db_type,
-        db_url,
-    };
+    let mut api_env = EnvFile::new(env::EnvFileType::Yaml, db_type, db_url);
+    let mut db_env = api_env.clone();
+    db_env.file_type = env::EnvFileType::DotEnv;
 
-    let mut db_env_file = api_env_file.clone();
-    db_env_file.file_type = env::EnvFileType::DotEnv;
+    let mut api_file =
+        std::fs::File::create(&api_config_path_absolute).expect("Failed to create API config file");
 
-    api_env_file.write(&api_config_path_absolute);
-    db_env_file.write(&db_config_path_absolute);
+    let mut db_file =
+        std::fs::File::create(&db_config_path_absolute).expect("Failed to create DB config file");
+
+    api_env.write(&mut api_file, true);
+    db_env.write(&mut db_file, false);
 }
 
 pub async fn stop_container(