Improve testability and remove boxing

Leverage generics to remove the extra heap allocation for the response
handlers using Dao's. Also moved some of the environment variables to
app state to allow for easier testing.

src/testhelpers.rs

@@ -1,6 +1,7 @@
-use actix_web::body::MessageBody;
-use actix_web::{body::BoxBody, HttpResponse};
-use serde::de::DeserializeOwned;
+use actix_web::{
+    body::{BoxBody, MessageBody},
+    HttpResponse,
+};
 
 use crate::database::{models::User, UserDao};
 use std::cell::RefCell;
@@ -65,17 +66,3 @@ impl BodyReader for HttpResponse<BoxBody> {
         std::str::from_utf8(&body).unwrap().to_string()
     }
 }
-
-pub trait TypedBodyReader<T>
-where
-    T: DeserializeOwned,
-{
-    fn read_body(self) -> T;
-}
-
-impl<T: DeserializeOwned> TypedBodyReader<T> for HttpResponse<BoxBody> {
-    fn read_body(self) -> T {
-        let body = self.read_to_str();
-        serde_json::from_value(serde_json::Value::String(body.clone())).unwrap()
-    }
-}