UP-3714 - Add show hidde toggle possibility on the sidebar

To activate this feature edit universality.xsl and see params  USE_SIDEBAR_TOGGLE and SIDEBAR_TOGGLE_INIT to activate it (only available for authentiocated users, but could be modified to be avalable for guest user - see in columns.xsl for that). Also see on file up-sidebar-improved.js to set the sessionID if isn't named as JSESSIONID, it's usefull to save user preferences of hidden elements in the sidebar during navigation, but could work without it if you don't care of saving user preferences between each pages.


This commit is dependant on https://github.com/Jasig/uPortal/pull/131, so this branch was created from.