XWIKI-9516: Create a new Wiki API that replaces xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Bug fix: XWiki.XWikiPreferences was not copied from template
Merge pull request #206 from gdelhumeau/master

XWIKI-9516: Create a new Wiki API that replaces xwiki-platform-wiki-manager and xwiki-platform-workspace.
* Bug fix: XWiki.XWikiPreferences was not copied from template