Remove section and sector tag controls for Publisher content.

DO NOT MERGE WITHOUT:
- [x] Code review
- [x] Coordination with these tickets: https://github.com/alphagov/publisher/pull/270 and https://github.com/alphagov/publisher/pull/276

https://www.pivotaltracker.com/story/show/79293166

This functionality is moving to Publisher.

Before:
![screenshot 2014-10-27 13 24 58](https://cloud.githubusercontent.com/assets/109225/4791832/f66e6426-5de0-11e4-9cab-b764a10ab37d.png)

After:
![screenshot 2014-10-27 13 32 46](https://cloud.githubusercontent.com/assets/109225/4791834/fb34b1fe-5de0-11e4-8bbe-6e664e9559cf.png)