feat(cfw): add data source to get the list of CFW black white lists

[profoundwu]

What this PR does / why we need it: add data source to get the list of CFW black white lists Which issue this PR fixes: (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged) fixes #xxx

Special notes for your reviewer:

Release note:

1. add data source to get the list of CFW black white lists

PR Checklist

• [x] Tests added/passed.
• [x] Documentation updated.
• [x] Schema updated.

Acceptance Steps Performed

make testacc TEST="./huaweicloud/services/acceptance/cfw" TESTARGS="-run TestAccDataSourceCfwBlackWhiteLists_basic"
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./huaweicloud/services/acceptance/cfw -v -run TestAccDataSourceCfwBlackWhiteLists_basic -timeout 360m -parallel 4
=== RUN   TestAccDataSourceCfwBlackWhiteLists_basic
=== PAUSE TestAccDataSourceCfwBlackWhiteLists_basic
=== CONT  TestAccDataSourceCfwBlackWhiteLists_basic
--- PASS: TestAccDataSourceCfwBlackWhiteLists_basic (88.07s)
PASS
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/cfw       88.167s

[houpeng80]

/lgtm

[Jason-Zhang9309]

/approve