ciwatch needs to also track CI's comments without a job

[Mikhail S Medvedev]

A CI can report a failure not associated with any job. E.g. if a patch failed to merge. While it can be argued if a third-party CI should comment in this case, ciwatch should keep track of all CI's activity. In this case, it can make it easier to prevent unwanted activity from a third-party CI.

On the ciwatch UI there is currently plenty of space in a row that is occupied by CI's name. That space can be reused to show an activity not associated with a particular job.