Several updates and fixes

- Removed all `thread::sleep` and use `tokio::time::sleep` now.
  This solves an issue with updating to Bullseye ( Resolves #1998 )
- Updated all Debian images to Bullseye
- Added MiMalloc feature and enabled it by default for Alpine based images
  This increases performance for the Alpine images because the default
  memory allocator for MUSL based binaries isn't that fast
- Updated `dotenv` to `dotenvy` a maintained and updated fork
- Fixed an issue with a newer jslib (not fully released yet)
  That version uses a different endpoint for `prelogin` Resolves #2378 )

src/api/core/accounts.rs

@@ -599,12 +599,11 @@ async fn password_hint(data: JsonUpcase<PasswordHintData>, conn: DbConn) -> Empt
                 // There is still a timing side channel here in that the code
                 // paths that send mail take noticeably longer than ones that
                 // don't. Add a randomized sleep to mitigate this somewhat.
-                use rand::{thread_rng, Rng};
-                let mut rng = thread_rng();
-                let base = 1000;
+                use rand::{rngs::SmallRng, Rng, SeedableRng};
+                let mut rng = SmallRng::from_entropy();
                 let delta: i32 = 100;
-                let sleep_ms = (base + rng.gen_range(-delta..=delta)) as u64;
-                std::thread::sleep(std::time::Duration::from_millis(sleep_ms));
+                let sleep_ms = (1_000 + rng.gen_range(-delta..=delta)) as u64;
+                tokio::time::sleep(tokio::time::Duration::from_millis(sleep_ms)).await;
                 Ok(())
             } else {
                 err!(NO_HINT);
@@ -626,12 +625,16 @@ async fn password_hint(data: JsonUpcase<PasswordHintData>, conn: DbConn) -> Empt
 
 #[derive(Deserialize)]
 #[allow(non_snake_case)]
-struct PreloginData {
+pub struct PreloginData {
     Email: String,
 }
 
 #[post("/accounts/prelogin", data = "<data>")]
 async fn prelogin(data: JsonUpcase<PreloginData>, conn: DbConn) -> Json<Value> {
+    _prelogin(data, conn).await
+}
+
+pub async fn _prelogin(data: JsonUpcase<PreloginData>, conn: DbConn) -> Json<Value> {
     let data: PreloginData = data.into_inner().data;
 
     let (kdf_type, kdf_iter) = match User::find_by_mail(&data.Email, &conn).await {