feat: add way to fetch and join invites from /invites/{id}

src/api/v1/invites/mod.rs

@@ -0,0 +1,9 @@
+use actix_web::{web, Scope};
+
+mod id;
+
+pub fn web() -> Scope {
+    web::scope("/invites")
+        .service(id::get)
+        .service(id::join)
+}