Rebuild actix-identity on top of actix-session (#246)

Co-authored-by: Rob Ede <robjtede@icloud.com>

actix-identity/tests/integration/fixtures.rs

@@ -0,0 +1,17 @@
+use actix_session::{storage::CookieSessionStore, SessionMiddleware};
+use actix_web::cookie::Key;
+use uuid::Uuid;
+
+pub fn store() -> CookieSessionStore {
+    CookieSessionStore::default()
+}
+
+pub fn user_id() -> String {
+    Uuid::new_v4().to_string()
+}
+
+pub fn session_middleware() -> SessionMiddleware<CookieSessionStore> {
+    SessionMiddleware::builder(store(), Key::generate())
+        .cookie_domain(Some("localhost".into()))
+        .build()
+}