No Hide/Publish rights for Admin on a blog post created by a normal user

I’ve drafted a fix for this: https://github.com/xwiki-contrib/application-blog/pull/136

What changed

• The hide/show icon of a published blog post is now shown to every user who can edit the post, not only to its creator. Admins can hide or show a post written by another user.

Please note: This relies on BLOG-172 and BLOG-173

Before BLOG-172 the post would have been restricted to the admin who hid it, and its author would have lost access.