Add SWR organization resource

[niuzhenguo]

What this PR does / why we need it:

Added new resource SWR organization.

Which issue this PR fixes:
(optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged)
fixes #428

PR Checklist

• Tests added/passed.
• Documentation updated.
• Schema updated.

Acceptance Steps Performed

make testacc TEST='./huaweicloud' TESTARGS='-run=TestAccSWROrganization_basic'
TF_ACC=1 go test ./huaweicloud/ -v -run=TestAccSWROrganization_basic -timeout 360m -parallel 4
=== RUN   TestAccSWROrganization_basic
=== PAUSE TestAccSWROrganization_basic
=== CONT  TestAccSWROrganization_basic
--- PASS: TestAccSWROrganization_basic (77.64s)
PASS
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud       77.660s