[erp5_web_renderjs_ui] Header: do not use acquired method in ready, as other gadgets may not be ready yet

by aborting the transaction after sending the diff tree to the user.
The diffs are still applied to the working copy.

Stop entering the login/password in the Javascript application.
Redirect instead to the data server (ERP5), which will be able to set a correct cookie/token.

Authentication is done on a separate Web Site to bypass some cache bug on IOS.

In case there is an error in the TALES experession and the page cannot
be rendered, then this page will silently be ignored.

They should be defined in a local property of the web section

This reverts commit 813bf150.

The RJS website is not related to hateoas directly