Fix GH actions and make concepts deterministic

[alistairewj]

• Makes concepts consistent across SQL dialects; this mostly involved removing sources of non-determinism, and caught a few bugs (biggest impact was the suspicion of infection had a non-determinism bug which made ~1% of records potentially flip - but no impact on the downstream sepsis query). Mostly these are on the order of impacting ~0.1% of rows.
  • first_day_gcs.sql, first_day_rrt.sql, oxygen_delivery.sql, suspicion_of_infection.sql
• GH actions now orchestrated from a CI, wget with retries to avoid flakiness, cache nicely, and should all work
• Set the postgres CI to use byte-order (C) collation to fix a very tricky non-determinism bug!
• added a few missing concepts to postgres-make-concepts.sql
• added indexes to postgres derived tables - sofa was taking ages to build, now just a few minutes
• bg now uses specimen_id so we don't incorrectly aggregate over samples taken at the same charttime
• heart rhythm now concatenates rhythms together rather than taking the alphabetical max when more than 1 is documented for a given chart time