publish field must not be editable

[rymsha]

Editing of publish info (start-end) date was implemented in CS to fixup publishing dates on content migrated from old versions of CMS.

Editing is possible only when content is already published - and when dates changed - actual change is applied on a draft content in whatever state it is now and required to press "Publish" anyway.

content publishing online dates should be solely defined by publish dialog instead.