It turns out that `was_rewarded` is a pretty bad heuristic if you ever
kill a boss a second time per week (basically, was_rewarded=false does
not imply that the boss was unsuccessful). Therefore, we need a proper
detection of when a fight failed and when a fight succeeded.

This is the first batch that implements this as part of the Analyzer
trait for bosses of wings 1 to 4.

It turns out that the different encounters do require quite some
encounter-specific logic, not only to determine whether the CM was
activated, but also to determine whether the fight was successful, the
duration of the fight, later the phases, ...

Wrapping all of this in pre-defined "triggers" (like CmTrigger) feels
like it will be a bit unfitting, so with this patch we have introduced
the evtclib::Analyzer, which can be used to analyze the fights.
Currently, the whole CM detection logic has been moved to this new
interface, and soon we also want the success-detection logic in there.

The tests pass and the interface of Log::is_cm is unchanged.