Move creation of scoped db connection based on workspace to a middleware

[ShubhranshuSanjeev]

Example

pub async fn create(
    state: web::Data<AppState>,
    _auth: AuthenticatedRequest,
    ws: Workspace,
    body: web::Json<CreateJob>,
) -> Result<HttpResponse, AppError> {
    let trigger = TriggerType::from_str_val(&body.trigger)
        .ok_or_else(|| AppError::InvalidRequest(format!("Invalid trigger: {}", body.trigger)))?;

    let mut conn = kronos_common::db::scoped::scoped_connection(&state.pool, &ws.0.schema_name)
        .await
        .map_err(AppError::from)?;