Improve aggregation

Adds the EngineHandler struct
Removes vulnerability where an attacker could send requests cookies with fake engine names and crash the server.
Merged RawSearchResult and SearchResult, as they were functionally identical.

src/server/routes.rs

@@ -7,6 +7,7 @@ use std::fs::read_to_string;
 use crate::{
     cache::cacher::RedisCache,
     config::parser::Config,
+    engines::engine_models::EngineHandler,
     handler::public_paths::public_path,
     results::{aggregation_models::SearchResults, aggregator::aggregate},
 };
@@ -175,12 +176,19 @@ async fn results(
             {
                 Some(cookie_value) => {
                     let cookie_value: Cookie = serde_json::from_str(cookie_value.name_value().1)?;
+
+                    let engines = cookie_value
+                        .engines
+                        .iter()
+                        .filter_map(|name| EngineHandler::new(name))
+                        .collect();
+
                     aggregate(
                         query,
                         page,
                         config.aggregator.random_delay,
                         config.debug,
-                        cookie_value.engines,
+                        engines,
                         config.request_timeout,
                     )
                     .await?