Enable navigation title by default for all content objects

[tisto]

Having the option to choose a different navigation title is essential for a CMS. When you have long page titles, you have to shorten them for the navigation and the breadcrumbs. Therefore this option should be present by default in Plone.

cc @sneridagh

[davisagli]

@tisto The option is present: we have the navtitle behavior, which can be enabled. Did you mean that it should be enabled by default for all content types in a new site? We can easily make that change without any backwards-compatibility problem, since it would only apply to new sites (if we don't write an upgrade step).

[tisto]

@davisagli yes. The navtitle behavior should be enabled by default IMO. We used to have a folder and a default view that can have different titles in Plone. This option is gone since we moved to folderish pages. Therefore we have to enable the navtitle behavior by default to have the same functionality.