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/Cargo.toml

@@ -15,3 +15,4 @@ tokio = { version = "1.47.0", features = ["full"] }
 url = "2.5.7"
 clap = { version = "4.5.48", features = ["derive", "env"] }
 path-clean = "1.0.1"
+serde_json = "1.0.145"