Add the possibility to distinguish different accounts of the same user on the UI

Sometimes we have several accounts created or automatically imported (ex : from LDAP) in the wiki for the same user and the different XWiki accounts shares the same information (first name, last name ...etc.), so, it is sometimes difficult to distinguish between the different accounts on the pages UI because only the full name of the users is displayed (ex : on the page history, page author, page creator ...). The only way available FTM to quickly distinguish between the different account is to hover over the user page link.

The objective of this ticket is to add a wiki configuration that allows the display of the username next to the user full name on the different locations where the user full name is displayed, for example : John Doe (JohnDoe). Even better allow to control the format of the displayed user information, for examples :

• By default : $firstName $lastName
• $lastName $firstName
• $firstName $lastName ($userName)
• ...