feat: Add support for organization rule suites

[JamBalaya56562]

Fixes: #4641.
Closes: #4482.

Supersedes #4482 by @ralucas, which has been inactive since the review in late August. This builds on that implementation and addresses the open review comments. Thanks to @ralucas for the original work.

This adds the organization rule suites endpoints:

Method	Endpoint
OrganizationsService.ListRuleSuites	GET /orgs/{org}/rulesets/rule-suites
OrganizationsService.GetRuleSuite	GET /orgs/{org}/rulesets/rule-suites/{rule_suite_id}

Changes from #4482, following the review there:

• ListRuleSuitesOptions covers all of the documented query parameters (ref, repository_name, time_period, actor_name, rule_suite_result, evaluate_status) and embeds ListOptions for page and per_page.
• The methods are named ListRuleSuites and GetRuleSuite, since Organization is redundant on OrganizationsService.
• The file is named orgs_rule_suites.go.
• The URLs are built with the usual u := fmt.Sprintf(...) / addOptions(u, opts) pattern.
• The tests check the query parameters with testFormValues and the error paths with testBadOptions/testNewRequestAndDoFailure in the main test functions, and use referenceTimestamp.

RuleSuite, RuleEvaluation, and RuleEvaluationSource have every property of the rule-suites and rule-suite response schemas. The generated ListRuleSuitesIter iterator is included.

The repository-level rule suites endpoints are still missing and can be added separately.

Verified locally: go build ./..., go vet -tags integration ./test/integration/, go test ./... (100% coverage of both methods and the iterator), generated files idempotent, script/metadata.sh check, and custom-gcl 0 issues.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.62%. Comparing base (fef0352) to head (e044aa5).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #4642   +/-   ##
=======================================
  Coverage   98.61%   98.62%           
=======================================
  Files         199      200    +1     
  Lines       18694    18730   +36     
=======================================
+ Hits        18436    18472   +36     
  Misses        258      258           

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[gmlewis]

Thank you, @JamBalaya56562!
LGTM.
Awaiting second LGTM+Approval from any other contributor to this repo before merging.

cc: @stevehipwell - @Not-Dhananjay-Mishra