Fix workspace issues related to the fact that the local Admin is missing

In a workspace, due to the fact that the local Admin user does not exist, there are some registration problems of certain features:

• Wiki Macros are not registered (done in XWIKI-7315)
• Application Administration sections are not while using XWiki.ConfigurableClass
• XWiki.StyleSheetExtension and XWiki.JavaScriptExtension elements are not registered and impact the functionality of applications such as Annotations
• Pages requiring PR by using the XWiki.RequiredRightClass are not functional

The chosen solution is to identify all of these cases by doing a search for documents containing objects of the above mentioned classes and saving them with the current (admin) user. This operation is performed at the install step, when an admin installs Workspaces and creates the workspace template.