MDL-40062 mod_forum: convert forum instance list
MDL-40062 mod_forum: Convert discussion viewed event
MDL-40062 mod_forum: remove debugging add_to_log() calls

The Moodle log is not the place for these kind of messages
MDL-40062 mod_forum: remove subscribeall/unsusbcribeall add_to_log

Now individual subscriptions will fire events, there is no need for a
catch all.
MDL-40062 mod_forum: remove read tracking log entries

Read tracking individual log entries do not provide enough reliable
information, as the posts can be marked as read automatically after
emailing or an expiry period.
MDL-40062 mod_forum: course_searched event
MDL-40062 mod_forum: Add forum_viewed event
MDL-40062 mod_forum: Discussion events

* discussion_created
* discussion_deleted
* discussion_moved
MDL-40062 mod_forum: subscription events

Events for forum mail subscriptions

* subscription_created
* subscription_deleted
MDL-40062 mod_forum: read tracking events
MDL-44062 mod_forum: subscribers_viewed event
MDL-40062 mod_forum: convert userreport log entry to event
MDL-40062 mod_forum: post events

* post_created
* post_updated
* post_deleted

Prune post (split discussion) has been converted to multiple events as
splitting a post actually means new discussion created.
MDL-40062 mod_forum: add event unit tests