LDEV-3171: Give a Monitor an option to remove learner's content from activities when moving him backwards in a sequence. Implementation of content-removing method for most of tools.
LDEV-3070: Fix few minor errors in Tools. Pass notifyCloseURL to proper authoring page in some Tools. Make generation of Tool content a non read-only operation as it starts a database transaction which is later used for writing.
LDEV-3070: Add single activity lessons wizard, first implementation iteration. Some changes were not committed as they interfere with old index page design.