Remove CIP.by_type which is not being used.

Method was causing admin filter to fail as it shadowed Edition.by_type which had
a different meaning.
Add ordering and hide_type to EditionFilter.

These will be used in the CorporateInformationPage index controller.

Also add CorporateInformationPage to list of edition types for filtering.
Use EditionFilter on CIP index page.

Params are hard-coded as the page only ever displays the full list of CIPs for
an organisation.