Remove the `alternative_title` field when presenting artefacts

This field is no longer supported in the Publisher application now
that alphagov/publisher#292 has been merged.
Merge pull request #206 from alphagov/remove-alternative-title-field-from-presenter

Remove the `alternative_title` field when presenting artefacts
Replace expectations with need_to_know

www.agileplannerapp.com/boards/173808/cards/8707

Expectations are replaced with freeform govspeak field need_to_know.
Related:
https://github.com/alphagov/govuk_content_models/pull/257/files?w=1
https://github.com/alphagov/govuk_content_models/pull/258
https://github.com/alphagov/publisher/pull/321
Merge pull request #207 from alphagov/need-to-know

Replace expectations with need_to_know