feat(cfw): add data source to get a list of CFW protection rules.

[profoundwu]

What this PR does / why we need it:
add data source to get a list of CFW protection rules.
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 a list of CFW protection rules.

PR Checklist

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

Acceptance Steps Performed

make testacc TEST="./huaweicloud/services/acceptance/cfw" TESTARGS="-run TestAccDataSourceCfwProtectionR ules_basic"
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./huaweicloud/services/acceptance/cfw -v -run TestAccDataSourceCfwProtectionRules_basic -timeout 360m -parallel 4
=== RUN   TestAccDataSourceCfwProtectionRules_basic
=== PAUSE TestAccDataSourceCfwProtectionRules_basic
=== CONT  TestAccDataSourceCfwProtectionRules_basic
--- PASS: TestAccDataSourceCfwProtectionRules_basic (354.27s)
PASS
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/cfw       354.341s

[github-actions]

This PR exceeds the recommended size of 1000 lines. Please make sure you are NOT addressing multiple issues with one PR. Note this PR might be rejected due to its size.

[github-actions]

This PR exceeds the recommended size of 1000 lines. Please make sure you are NOT addressing multiple issues with one PR. Note this PR might be rejected due to its size.

[github-actions]

This PR exceeds the recommended size of 1000 lines. Please make sure you are NOT addressing multiple issues with one PR. Note this PR might be rejected due to its size.

[houpeng80]

/lgtm

[github-actions]

This PR exceeds the recommended size of 1000 lines. Please make sure you are NOT addressing multiple issues with one PR. Note this PR might be rejected due to its size.

[Jason-Zhang9309]

/approve

[github-ci-robot]

This PR has been approved by: @Jason-Zhang9309

/approve

[Jason-Zhang9309]

/lgtm