Prevent creating ports having reserved ids

**Describe the bug**
Virtual ports having ids that are reserved identifiers can be created.

**Expected behavior**
`400 Bad Request` should be returned by the `POST /ports` API call when supplying one of the following ids:
 * `value`
 * `add`
 * `remove`
 * `definitions`
 * `webhooks`
 * `reverse`
