WIKI-890: [Iframe] Impossible to add attachment to wiki page

Fix description:
- Avoid access main page in case of iframe
WIKI-844: Cannot open wiki page when wiki portlet locates in new site

Fix description:
* Rebuild the correct page link in UITreeExplorer.
WIKI-842 [IE8] Difficult to close Preview Window

Fix description:
* Define the position for action icon inside Preview Header.