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

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

* Fix bug.
Merge pull request #201 from gdelhumeau/new-wiki-api

XWIKI-9516: Create a new Wiki API that replaces xwiki-platform-wiki-mana...