Cleanups and Fixes for Emergency Access

- Several cleanups and code optimizations for Emergency Access
- Fixed a race-condition regarding jobs for Emergency Access
- Some other small changes like `allow(clippy::)` removals

Fixes #2925

src/db/models/user.rs

@@ -364,7 +364,7 @@ impl User {
 }
 
 impl Invitation {
-    pub fn new(email: String) -> Self {
+    pub fn new(email: &str) -> Self {
         let email = email.to_lowercase();
         Self {
             email,