[uicfg] give a set_fields_order method to the primary view display control
Hence it is nicely symmetrical with the fields kwargs.
Closes #2741963.
Document: cubicweb-docTitle: CubicWeb documentationAuthor: LogilabAbstract: Some base documentation for CubicWeb users and developpersSection: Apps/ProgrammingFormat: HTMLIndex: /usr/share/doc/cubicweb-documentation/index.htmlFiles: /usr/share/doc/cubicweb-documentation/*.html