Remove num-to-keep from most jobs, as this leads to keeping the build
logs for a much shorter timeline than desired. For example the
gerrit-binpkgs-deb job that runs for most projects when pushing patches
to jenkins reaches the 120 limit in less than 24h - and so when clicking
the link on a failed build from yesterday it is already deleted.
Instead just keep the logs for the last 30 days, no matter how many were
submitted on one day. Storing logs doesn't take up much space.
Remove the artifact-days-to-keep and artifact-num-to-keep lines, as they
don't have an effect. For jobs that do have artifacts, the actual value
is min(days-to-keep,artifact-days-to-keep) and same with num-to-keep.
While at it, increase the ttcn3-testsuites build-discarder to 120 days
as this means more data will show up in the test result analyzer at
which we look frequently.
Change-Id: Iec5c22c7fcf6c1fd2db71611045f15dc6580ed86