Add org unit data source

[danquack]

Description

Adds an organizational_unit data lookup for a single entity.

Relations

Closes #22909

References

Output from Acceptance Testing

% TF_ACC=1 make testacc TESTS=TestAccOrganizationalUnitDataSource_ PKG=organizations
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/organizations/... -v -count 1 -parallel 20 -run='TestAccOrganizationalUnitDataSource_'  -timeout 180m
=== RUN   TestAccOrganizationalUnitDataSource_basic
--- PASS: TestAccOrganizationalUnitDataSource_basic (25.26s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/organizations      27.338s

[github-actions]

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[ewbankkit]

LGTM 🚀.

% make testacc TESTARGS='-run=TestAccOrganizations_serial/OrganizationalUnit' PKG=organizations
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./internal/service/organizations/... -v -count 1 -parallel 20  -run=TestAccOrganizations_serial/OrganizationalUnit -timeout 180m
=== RUN   TestAccOrganizations_serial
=== PAUSE TestAccOrganizations_serial
=== CONT  TestAccOrganizations_serial
=== RUN   TestAccOrganizations_serial/OrganizationalUnit
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/ChildAccountsDataSource_basic
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/DescendantAccountsDataSource_basic
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/PluralDataSource_basic
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/basic
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/disappears
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/update
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/tags
=== RUN   TestAccOrganizations_serial/OrganizationalUnit/DataSource_basic
--- PASS: TestAccOrganizations_serial (253.25s)
    --- PASS: TestAccOrganizations_serial/OrganizationalUnit (253.25s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/ChildAccountsDataSource_basic (19.81s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/DescendantAccountsDataSource_basic (31.30s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/PluralDataSource_basic (23.93s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/basic (27.58s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/disappears (21.07s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/update (43.95s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/tags (61.44s)
        --- PASS: TestAccOrganizations_serial/OrganizationalUnit/DataSource_basic (24.17s)
PASS
ok  	github.com/hashicorp/terraform-provider-aws/internal/service/organizations	258.977s

[ewbankkit]

@danquack Thanks for the contribution 🎉 👏.

[github-actions]

This functionality has been released in v5.18.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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