[DOC] Document create or update alias API

[gaobinlong]

What do you want to do?

• [ ] Request a change to existing documentation
• [x] Add new documentation
• [ ] Report a technical problem with the documentation
• [ ] Other

Tell us about your request. Provide a summary of the request.

We need to document the usage of the create or update alias API.

*Version: List the OpenSearch version to which this issue applies, e.g. 2.14, 2.12--2.14, or all.

All version

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

[Naarcha-AWS]

Also relates to #3790