Implement data rollup/archival/deletion policy in testresults in postgresql

Currently the table test_results_raw has grown to a size of ~6G rows.

While we want to keep (some of) the old data and query them, we should do this optimally, given that the old data is read-only and very compressible.

Possibilities:

• PARTITION tables based on workitem started_on timestamp, on a per-month basis
• Move archived tables to a TABLESPACE on a compressed filesystem

• • check first if the transparent compression of IT storage is good enough; this would make things much simpler.
• Use slow storage devices for old data
• Delete non-integration/nightly entries