Fix EZP-23584: Impossible to edit and publish the same content 2 times in a row

This is caused by https://github.com/yui/yui3/issues/1982 and the fix introduces
a workaround for that.
Fix EZP-23583: Added the form handling in the server side part
Improved the templates in the section part to improve the style of the page
Added the requirement on the eZ Publish version in the README
[ci skip]
Merge pull request #124 from ezsystems/admin_tpl_improved

Improved the templates in the section part to improve the style of the page
Merge pull request #123 from ezsystems/ezp-23583_admin_forms

EZP-23583: As an editor, I want to be able to use forms in the administration part of the PlatformUI App
Merge pull request #122 from ezsystems/ezp-23584_edit_two_times

Fix EZP-23584: Impossible to edit and publish the same content 2 times in a row
Updated YUI to 3.18.1
Fix EZP-23670: Install YUI3 via bower
EZP-23670: use YUI3 installed with bower in the unit tests
EZP-23670: make the unit tests in coverage mode are running