Job that collects disk usage and removes CI builds older than 4 weeks old.

In theory it can:

• delete old workspaces (without deleting jobs), eg.,
  • /jobs/genie.webtools/ and *DEPRECATED/workspace/*
• delete old builds (on build.eclipse)eg.,
  • /shared/webtools/committers/wtp-R3.10.0-I/ and 2018052*
• delete old releases (on download.eclipse), eg.,
  • /home/data/httpd/download.eclipse.org/webtools/downloads/drops/R3.10.0/ and I-3.10.0-201806*