feat(cae): add new resource to manage timer rule

[wuzhuanhong]

What this PR does / why we need it:
Add new resource （huaweicloud_cae_timer_rule） to manage a timer rule for starting and stopping components.

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 new resource.
2. add corresponding document and acceptance test.

PR Checklist

• Tests added/passed.

./scripts/coverage.sh -o cae -f TestAccTimerRule_basic
Prepare to calculate the coverage the following command:
TF_ACC=1 go test "./huaweicloud/services/acceptance/cae" -v -coverprofile="./huaweicloud/services/acceptance/cae/cae_coverage.cov" -coverpkg="./huaweicloud/services/cae" -run TestAccTimerRule_basic -timeout 360m -parallel 10
=== RUN   TestAccTimerRule_basic
=== PAUSE TestAccTimerRule_basic
=== CONT  TestAccTimerRule_basic
--- PASS: TestAccTimerRule_basic (117.39s)
PASS
coverage: 36.2% of statements in ./huaweicloud/services/cae
ok      github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/cae       117.458s        coverage: 36.2% of statements in ./huaweicloud/services/cae

• Documentation updated.

• Schema updated.

• CheckDeleted.

  • a. During query operation (Read Context)
    aa. Resource not found
    

    ab. Related resources (parent resources) not found
    

  • b. During delete/disassociate/unbind operation (Delete Context)
    

    bb. Related resources (parent resources) not found
    

[wuzhuanhong]

./scripts/coverage.sh -o cae -f TestAccTimerRule_basic
Prepare to calculate the coverage the following command:
TF_ACC=1 go test "./huaweicloud/services/acceptance/cae" -v -coverprofile="./huaweicloud/services/acceptance/cae/cae_coverage.cov" -coverpkg="./huaweicloud/services/cae" -run TestAccTimerRule_basic -timeout 360m -parallel 10
=== RUN TestAccTimerRule_basic
=== PAUSE TestAccTimerRule_basic
=== CONT TestAccTimerRule_basic
--- PASS: TestAccTimerRule_basic (131.63s)
PASS
coverage: 25.7% of statements in ./huaweicloud/services/cae
ok github.com/huaweicloud/terraform-provider-huaweicloud/huaweicloud/services/acceptance/cae 131.702s coverage: 25.7% of statements in ./huaweicloud/services/cae