Updated authenticator TOTP

- Added security check for previouse used codes
- Allow TOTP codes with 1 step back and forward when there is a time
drift. This means in total 3 codes could be valid. But only newer codes
then the previouse used codes are excepted after that.

src/db/models/two_factor.rs

@@ -19,6 +19,7 @@ pub struct TwoFactor {
     pub atype: i32,
     pub enabled: bool,
     pub data: String,
+    pub last_used: i32,
 }
 
 #[allow(dead_code)]
@@ -47,6 +48,7 @@ impl TwoFactor {
             atype: atype as i32,
             enabled: true,
             data,
+            last_used: 0,
         }
     }