refactor: move Solar struct to mqtt module

Software/MainBoard/rust/src/main.rs

@@ -84,12 +84,6 @@ enum WaitType {
     MqttConfig,
 }
 
-#[derive(Serialize, Deserialize, Debug, PartialEq)]
-struct Solar {
-    current_ma: u32,
-    voltage_ma: u32,
-}
-
 impl WaitType {
     fn blink_pattern(&self) -> u64 {
         match self {
@@ -1047,7 +1041,7 @@ async fn publish_mppt_state(
 ) -> FatResult<()> {
     let current = board.board_hal.get_mptt_current().await?;
     let voltage = board.board_hal.get_mptt_voltage().await?;
-    let solar_state = Solar {
+    let solar_state = mqtt::Solar {
         current_ma: current.as_milliamperes() as u32,
         voltage_ma: voltage.as_millivolts() as u32,
     };