Add Identity Card Number to User

Adds the ~~`id_number`~~ `identity_card_number` attribute and makes it available for the user to edit and see.

~~Need to add censor rules and include it in the initial request email.~~
```diff
-# <%= _('ID Number') %>: <%= @outgoing_message.info_request.user.identity_card_number %>
+# <%= _('Identity Card Number') %>: <%= @outgoing_message.info_request.user.identity_card_number %>
```