Add redis caching to getting user notifications and projects [MOD-540] (#723)

* Add redis caching to getting a user's project ids

* Run `cargo sqlx prepare` to update the sqlx-data.json

* Add redis caching for getting user notifications

* Fix new clippy warnings

* Remove log that shouldn't have been committed

* Batch insert of notifications (untested)

* sqlx prepare...

* Fix merge conflict things and use new redis struct

* Fix bug with calling delete_many without any elements (caught by tests)

* cargo sqlx prepare

* Add tests around cache invalidation (and fix bug they caught!)

* Some test reorg based on code review suggestions

src/database/models/flow_item.rs

@@ -49,19 +49,13 @@ impl Flow {
             .collect::<String>();
 
         redis
-            .set(
-                FLOWS_NAMESPACE,
-                &flow,
-                serde_json::to_string(&self)?,
-                Some(expires.num_seconds()),
-            )
+            .set_serialized_to_json(FLOWS_NAMESPACE, &flow, &self, Some(expires.num_seconds()))
             .await?;
         Ok(flow)
     }
 
     pub async fn get(id: &str, redis: &RedisPool) -> Result<Option<Flow>, DatabaseError> {
-        let res = redis.get::<String, _>(FLOWS_NAMESPACE, id).await?;
-        Ok(res.and_then(|x| serde_json::from_str(&x).ok()))
+        redis.get_deserialized_from_json(FLOWS_NAMESPACE, id).await
     }
 
     pub async fn remove(id: &str, redis: &RedisPool) -> Result<Option<()>, DatabaseError> {