User logged delete it's forbidden

In user management of the Admin GUI we hide delete option.
Change messages for user unsuccessful login

Now shown different messages:

* When GeoStore it's unavailable
* When the user logged is not admin
* When the user is not found
Admin footer like maspstore for Admin GUI

* Add jquery to the login page
* Add about page from mapstore as jsp (and it's resources needed: logos and css)
* Add proxy for about page and security change to allow access to anonymous user
* Changes to footer.jsp to use the new jquery footer