Limit order input for new vocabulary entries

It is possible to add a vocabulary entry with order number greater than Integer.MAX_VALUE, resulting in a format exception when loading entries in a nuxeo-directory-suggestion.

Steps to reproduce:

1. In Web UI, navigate to Administration > Vocabularies. Select a Vocabulary (e.g. Nature) and add a new entry with Order greater than or equal to 2147483647.
2. Create a new Document, and attempt to populate the corresponding directory field with a value by clicking the nuxeo-directory-suggestion dropdown.

Expected result: vocabulary entries should appear under the dropdown

Actual result: dropdown remains displaying "Loading..." while java.lang.NumberFormatException is logged in console.