Reorganization of Main.WebHome to make it a full dashboard

Basically the idea is to allow Main.WebHome to be easily edited as a dashboard (now that XWIKI-116 was implemented), by clicking the Edit button (and automatically go in inline edit mode), but there are 2 things in the way:

• the welcome message is in the content of the page, and editing by default in inline mode would make it impossible to edit this message. The welcome message could be in a gadget on the main webhome, and the message itself would be relocated to a page, Main.Welcome. This should also help a bit with the translation of this page.
• the dashboard reuses Main.Dashboard dashboard, and because that one is written to work both on space webhome and on main webhome. Because of that all the gadgets are actually velocity scripts (velocity macros) and editing them does not actually edit the parameters of the gadgets themselves. With this reorganization, we would actually make it a dashboard defined in Main.WebHome.

A consequence of the change described in the first bullet is the rename of the page, since "Welcome to your wiki" should now be the title of the welcome gadget, to "Wiki Home" is simple enough, and illustrates very well its purpose (think of the breadcrumbs where Main.WebHome used to appear as "Welcome to your wiki" and now it will appear as "Wiki Home").

See the proposal mail at http://xwiki.markmail.org/thread/5lobnrtnjqnhiqsa .

In essence, for the user, it's only a slight visual reorganization (welcome message will move to a one of the columns instead of a text on top of the 2 columns), and the benefits are pretty great.