[PM-3565] Enforce higher minimum KDF (#3304)

Extract KDF logic into a new Range class. Increase minimum iterations for PBKDF.

src/Api/Controllers/AccountsController.cs

@@ -113,7 +113,7 @@ public class AccountsController : Controller
             kdfInformation = new UserKdfInformation
             {
                 Kdf = KdfType.PBKDF2_SHA256,
-                KdfIterations = 100000,
+                KdfIterations = AuthConstants.PBKDF2_ITERATIONS.Default,
             };
         }
         return new PreloginResponseModel(kdfInformation);