Refactor Gitea client and improve issue handling

Update the authorization header format in the Gitea client. Enhance issue details in work package creation and make `number` field public in the `Issue` struct.

src/gitea/client.rs

@@ -54,7 +54,7 @@ impl Client {
 
     pub async fn get<T: DeserializeOwned>(&self, url: Url) -> Result<T, GeneralError> {
         let mut headers = HeaderMap::new();
-        headers.append(AUTHORIZATION, self.token.parse()?);
+        headers.append(AUTHORIZATION, format!("token {}", self.token).parse()?);
         headers.append(ACCEPT, "application/json".parse()?);
 
         let client = ClientBuilder::new()