event_logs: Reduce query expression duplication

Created by: efritz

Some of these expressions are hard to remember, so I'm going to define them in one place.

• our DATE_TRUNC usage works as expected for days and months, but for weeks we need to do some clock arithmetic so that it starts on sunday, not monday
• user id expressions are also a bit tricky and are repeated more than necessary

Created by: codecov[bot]

Codecov Report

Merging #15665 (4fdfda2) into main (0356174) will increase coverage by 0.00%. The diff coverage is 80.00%.

@@           Coverage Diff           @@
##             main   #15665   +/-   ##
=======================================
  Coverage   52.40%   52.40%           
=======================================
  Files        1628     1628           
  Lines       81236    81239    +3     
  Branches     7136     7136           
=======================================
+ Hits        42570    42572    +2     
- Misses      34880    34881    +1     
  Partials     3786     3786           

Flag	Coverage Δ		*Carryforward flag
go	52.36% <80.00%> (+<0.01%)
integration	28.35% <ø> (ø)		Carriedforward from 0356174
storybook	27.19% <ø> (ø)		Carriedforward from 0356174
typescript	52.49% <ø> (ø)		Carriedforward from 0356174
unit	34.78% <ø> (ø)		Carriedforward from 0356174

*This pull request uses carry forward flags. Click here to find out more.

Impacted Files	Coverage Δ
internal/db/event_logs.go	53.11% <80.00%> (+0.59%)
cmd/repo-updater/repos/types.go	74.20% <0.00%> (-0.25%)