Move TURN config to separate config section

This renames:

turn_username -> turn.username
turn_password -> turn.password
turn_uris -> turn.uris
turn_secret -> turn.secret
turn_ttl -> turn.ttl

src/config.rs

@@ -81,15 +81,7 @@ pub(crate) struct Config {
     #[serde(default)]
     pub(crate) log_format: LogFormat,
     #[serde(default)]
-    pub(crate) turn_username: String,
-    #[serde(default)]
-    pub(crate) turn_password: String,
-    #[serde(default = "Vec::new")]
-    pub(crate) turn_uris: Vec<String>,
-    #[serde(default)]
-    pub(crate) turn_secret: String,
-    #[serde(default = "default_turn_ttl")]
-    pub(crate) turn_ttl: u64,
+    pub(crate) turn: TurnConfig,
 
     pub(crate) emergency_password: Option<String>,
 }
@@ -144,6 +136,28 @@ pub(crate) enum LogFormat {
     Json,
 }
 
+#[derive(Clone, Debug, Deserialize)]
+#[serde(default)]
+pub(crate) struct TurnConfig {
+    pub(crate) username: String,
+    pub(crate) password: String,
+    pub(crate) uris: Vec<String>,
+    pub(crate) secret: String,
+    pub(crate) ttl: u64,
+}
+
+impl Default for TurnConfig {
+    fn default() -> Self {
+        Self {
+            username: String::new(),
+            password: String::new(),
+            uris: Vec::new(),
+            secret: String::new(),
+            ttl: 60 * 60 * 24,
+        }
+    }
+}
+
 fn false_fn() -> bool {
     false
 }
@@ -213,10 +227,6 @@ fn default_log() -> EnvFilterClone {
         .expect("hardcoded env filter should be valid")
 }
 
-fn default_turn_ttl() -> u64 {
-    60 * 60 * 24
-}
-
 // I know, it's a great name
 pub(crate) fn default_default_room_version() -> RoomVersionId {
     RoomVersionId::V10

src/service/globals.rs

@@ -366,23 +366,23 @@ impl Service {
     }
 
     pub(crate) fn turn_password(&self) -> &String {
-        &self.config.turn_password
+        &self.config.turn.password
     }
 
     pub(crate) fn turn_ttl(&self) -> u64 {
-        self.config.turn_ttl
+        self.config.turn.ttl
     }
 
     pub(crate) fn turn_uris(&self) -> &[String] {
-        &self.config.turn_uris
+        &self.config.turn.uris
     }
 
     pub(crate) fn turn_username(&self) -> &String {
-        &self.config.turn_username
+        &self.config.turn.username
     }
 
     pub(crate) fn turn_secret(&self) -> &String {
-        &self.config.turn_secret
+        &self.config.turn.secret
     }
 
     pub(crate) fn emergency_password(&self) -> &Option<String> {