By default Global users cannot view a wiki

Here is the use case

• You have a farm
• A user that belongs to XWikiAllGroup on the farm
• This user logs on another wiki
• The user cannot see anything from that wiki

Reason: The rights are set by default to local groups and not for global groups. Global groups users don't have explicit rights by default with results in them not being able to view any page.

Suggestion: By default, we should have the same configuration for global groups and local groups for all wikis. This for the default groups XWikiAdminGroup and XWikiAllGroup