Updates manual_rsync_{GEO,LHO,LLO,VGO}.sh and test_rsync.sh
Changes to manual_rsync_{GEO,LHO,LLO,VGO}.sh address the issue in #39 (closed) ("DQXML gap filler script often runs after start of metric day") and partially addresses items described in #43 ("Refactor and improve manual_rsync scripts").
Changes to test_rsync.sh refactor the code a bit to make updates easier, update rsync tests to check both primary and secondary servers for LHO and LLO, and improve suggested test commands for all IFOs (GEO, KAGRA, LHO, LLO, and Virgo), which can be very useful for diagnosing rsync issues.