MDL-45916 tool_monitor: Adding xml file defining the db tables
MDL-46109 tool_monitor: Implement a class to get list of events and other related apis
MDL-45939 tool_monitor: Implement a class that represents a rule instance
MDL-46131 navigation: updates to navigation

This patch does the following:-
Start using proper key for course report node
Allow admin tools to hook into course navigation
MDL-46131 tool_monitor: Build the navigation tree for the tool
MDL-45919 tool_monitor: Add a subscription manager class
MDL-45918 tool_monitor: Rule manager class, unit tests and data generators.
MDL-45918 tool_monitor: Polish the code for rule manager and unit tests
MDL-45938 tool_monitor: Initial version of rule form.
MDL-45938 tool_monitor: Add a yui module to handle event selection dropdown
MDL-45938 tool_monitor: Add support for editing/creating a rule