[FEATURE] Add Search Capablity to Garvitino Docs

### Describe the feature

As a developer, I would love to search through the docs on the website https://gravitino.apache.org/docs/0.7.0-incubating/

but I couldnt find a search bar, it would be super helpful if we could have that.

### Motivation

_No response_

### Describe the solution

_No response_

### Additional context

_No response_

Start at the documentation site linked in the issue and identify its build and deployment configuration. Determine how the 0.7.0-incubating docs are generated and where site navigation is defined. Done means the published documentation has a usable search bar that returns relevant results across the docs.

Written by the indexing model from the issue text.