The log live report class should extend the log report class.

This issue was raised because, when we deprecated the update_users_and_courses_used() function in MDL-48595, we did not deprecate the same function in report_loglive.

Firstly we need to confirm whether this should have been done and, if so, we need to look at addressing that.

Secondly, and possibly as a means of addressing that, we are duplicating a lot of code in report/loglive/classes/table_log.php that exists in report/log/classes/table_log.php. If we were to do 'class report_loglive_table_log extends report_log_table_log' we could save duplicating a lot of code. It would also mean issues like MDL-48595 benefit the live log as well rather than it being forgotten.

This issue was created to investigate whether or not this is viable.