[DOCS] Enable Search for the dcos

[alabulei1]

Description

Now we don't support search for the docs. However, it's a must-have thing for users to find the content they need quickly.

Screenshots

No response

Additional information

Need to apply a token from docusaurus.

[kokamkarsahil]

The owner of the website have to apply at https://docsearch.algolia.com/apply/ to get token or someone who has obtain permission from the owner can apply.

There is another way to use local search for example: https://github.com/easyops-cn/docusaurus-search-local it's supports zn too

[alabulei1]

Thanks @kokamkarsahil