Fix adding a new user and don't allow to add non-local users

The user structure must provide the correct account source now.

modules/backend/src/main/scala/docspell/backend/ops/OCollective.scala

@@ -214,6 +214,9 @@ object OCollective {
         store.transact(RUser.findAll(collective, _.login))
 
       def add(s: RUser): F[AddResult] =
+        if (s.source != AccountSource.Local)
+          AddResult.failure(new Exception("Only local accounts can be created!")).pure[F]
+        else
           store.add(
             RUser.insert(s.copy(password = PasswordCrypt.crypt(s.password))),
             RUser.exists(s.login)

modules/store/src/main/scala/docspell/store/AddResult.scala

@@ -50,4 +50,6 @@ object AddResult {
     def fold[A](fa: Success.type => A, fb: EntityExists => A, fc: Failure => A): A =
       fc(this)
   }
+  def failure(ex: Exception): AddResult =
+    Failure(ex)
 }

modules/webapp/src/main/elm/Comp/UserForm.elm

@@ -85,6 +85,7 @@ getUser model =
         , email = model.email
         , state = state
         , password = model.password
+        , source = "local"
     }