Revert "⛔ config: deny unknown fields"

[zonyitoo]

Reverts #1106

There are some fields only for binaries:

shadowsocks-rust/src/config.rs

Lines 260 to 265 in a9601f3

	#[derive(Deserialize)]
	struct SSConfig {
	#[cfg(feature = "logging")]
	log: Option<SSLogConfig>,
	runtime: Option<SSRuntimeConfig>,
	}

.