Make WS to get permissions of users and groups public WS

The following WS are the only web services available to get permissions (and permission templates) of users and groups :

• api/permissions/users
• api/permissions/groups
• api/permissions/template_users
• api/permissions/template_groups

They are set as internal but they should become public.

It will also be a good opportunity to :

• Correctly handles the permissions 'applicationcreator' and 'portfoliocreator' in 'permission' parameter and in response
• Not return users name and email
• Not return groups description
• Remove 'projectId' usage
• Rename 'projectKey' to 'project'

Note that even if this WS was internal it could have been used as they were the only web services available to get this information : we should use the deprecation mechanism to properly redirect usage of 'projectKey' to 'project'