Add a new resource to manage Elasticsearch aliases.

The resource must:

• Be created in internal/elasticseach/index/alias
• Cover the full API (Create/Update, Get, Delete)
• Read the alias back after create/update operations. This should re-use the read code to ensure the resource state is consistently updated.
• Have full acceptance test coverage, using both indices and data streams across both create, and update workflows.
• All unit and acceptance tests must pass, the agent environment has running Stack instances which can be accessed via the default environment variables defined in Copilot instructions.

Original issue

Is your feature request related to a problem? Please describe.
Currently to update alias from one index to another, we need to take 2 steps in separate operations.

1. add to the new index
2. remove it from the old index

Also sometimes we don't want to allow multiple indices having the same alias but it can happen with the current way of managing alias separately in the index resource.

Describe the resource you would like to have implemented.
We would like to have alias resource to manage all the alias in the single resource to make it easier to apply multiple alias updates all at once.

Describe alternatives you've considered
Using index resource.

Additional context
Available APIs.

• Read
• Add/Delete