Prevent renaming device to reserved identifiers

**Describe the bug**
Device can now be renamed to any of the reserved identifiers.

**Expected behavior**
`400 Bad Request` should be returned by the `PATCH /device` API call when supplying one of the following names:
 * `value`
 * `add`
 * `remove`
 * `definitions`
 * `webhooks`
 * `reverse`
