feat: Add CreatedAt and UpdatedAt to Ruleset

[ivanmartos]

This PR will expose fields CreatedAt and UpdatedAt for Ruleset

Closes #3315

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[gmlewis]

Thank you, @ivanmartos !
Please run go generate ./... and push (not force-push) the changes to this PR as explained in step 4 of CONTRIBUTING.md.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.05%. Comparing base (2b8c7fa) to head (8f11111).
Report is 143 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3316      +/-   ##
==========================================
- Coverage   97.72%   93.05%   -4.67%     
==========================================
  Files         153      172      +19     
  Lines       13390    11760    -1630     
==========================================
- Hits        13085    10943    -2142     
- Misses        215      723     +508     
- Partials       90       94       +4     

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[gmlewis]

Thank you, @ivanmartos !
LGTM.
Merging.