Extractors depend on the inputs:edit permission

We want to give a moderator role the possibility to work with the extractors.
If we give it the role for the extractors, it can also create them, but not edit them later.
"extractor:create",
"extractor:delete",
"extractor:edit",
"extractor_order:update",
"extractor:update",

Only with the right inputs:edit this is possible.
Which again gives more rights than it should and violates our guidelines.

* Graylog Version: 2.4.6
* Elasticsearch Version: 5.x