Add support for the time ("Date") macro

[oanat]

Steps to reproduce:

• Create a page in Confluence and use the Date macro (from the "+" menu):

• Export the space from Confluence
• Ran the Confluence migration in XWiki

Result:
The XWiki page displays velocity errors for a missing time macro

Expected result: display the information as a date similar to the Confluence page

[raphj]

Done @snazare

(sn, sorry for the wrong ping)

[sn]

@raphj Good work!