Add new smoke test section into test manifest schema

[zelinh]

Subtask from #4551

A new smoke-test section should be added to the test manifest to specify which component were onboarded for smoke tests.

It could be looked like this

components:
  - name: opensearch
    smoke-test:
      test-spec: opensearch.yml
  - name: alerting
    integ-test:
      ...
    bwc-test:
      ...
    smoke-test:
      test-spec: alerting.yml
  - ...

In the above example, opensearch & alerting are onboarded with smoke test. In the test-spec section, it would point to a component spec yaml file which specifies the API request path for the smoke tests to run on.

[zelinh]

The smoke_test is added into our test manifest. Close this issue for now.