Clean up throttler table more aggressively
First commit:
winery: add indexes on the updated column of the throttler tables
All throttler queries filter these tables using ranges of the updated
column, so adding a block range index makes these queries much more
efficient.
Ref. swh/infra/sysadm-environment#5388
Second commit:
winery: clean up the throttler tables more aggressively
Make the throttler window of measurement a module-level constant, and
clean up stale rows that are twice as old as the window (10 minutes)
instead of one month old.