feat(live): add a new resource to generate a sign URL

[ruwenqiang123]

What this PR does / why we need it:

Add a new resource to generate a sign URL.

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. support a new resource to generate a sign URL.
2. 2.support related document and acceptance test.

PR Checklist

• Tests added/passed.

$ make testacc TEST="./huaweicloud/services/acceptance/live" TESTARGS="-run TestAccUrlAuthentication_basic"
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./huaweicloud/services/acceptance/live -v -run TestAccUrlAuthentication_basic -timeout 360m -parallel 4
=== RUN   TestAccUrlAuthentication_basic
=== PAUSE TestAccUrlAuthentication_basic
=== CONT  TestAccUrlAuthentication_basic
--- PASS: TestAccUrlAuthentication_basic (433.68s)
PASS
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/live      433.771s

• Documentation updated.

• Schema updated.

• CheckDeleted.

  • a. During query operation (Read Context)
    aa. Resource not found
    >>>>>> Paste the screenshot here <<<<<<

  • b. During delete/disassociate/unbind operation (Delete Context)
    ba. Resource not found
    >>>>>> Paste the screenshot here <<<<<<