UP-3760 - Adding portlet on locked tab/column

This commit is only a try to remove whitespace before all other commit
of this PR.
UP-3760 - Adding portlet on locked tab/column

Solve ISSUE in adding a management of the error in the controller with a local message to return of the
user in waiting this is managed and shown in the UI. So an improvment of
the UI still exist after this commit.
UP-3760 - Adding portlet on locked tab/column

Adding a content where to show messages returned from api actions.
UP-3760 - Adding portlet on locked tab/column

This commit is to hide in the portal gallery the menu add portlet when
there isn't a column that as the class canAddChildren, also this update
the gallery menu when a column is added or deleted
UP-3760 - Adding portlet on locked tab/column

Add filtering on locked tab to avoid to purpose to the user to add the
used portlet in a locked tab.