Optimize disk usage by deleting successful build logs after 7 days.

[RedYetiDev]

(CC @ryanaslett)

At the moment, Jenkins stores build logs for 21 days (both successes and failures). Given the number of CIs executed daily, this leads to a huge volume of logs.

Since successful build logs don’t offer much valuable insight, how about reducing their retention period to just 7 days?

[richardlau]

Given the number of CIs executed daily, this leads to a huge volume of logs.

I'm not sure that the past week hasn't been an anomaly in terms of number of builds.