Replace search from Algolia to easyops-cn/docusaurus-search-local

[3gf8jv4dv]

For Firefox users, Algolia doesn't seem to be able to properly enter Chinese characters (or maybe CJK characters, but I haven't tested). This is definitely a pain for me as a heavy firefox user.

I noticed an alternative: easyops-cn/docusaurus-search-local. This one is optimized for Chinese search. It is now used by some famous projects such as Shields.io. For me, it's a great experience on Firefox.

I don't know if you are willing to accept it. If allowed, I can submit a PR. I'm glad I recently learned to develop the Docusaurus site in local environments.

[lyswhut]

I'll take a look at it sometime