Update usage documentation and use cases

[bigboss2063]

Since the way nutsdb is used has changed, some documents and use cases have not been updated and need to be updated now.

[TremblingV5]

I see that there's a repo named nutsdb-docs in the repos list of NutsDB. So I think it can be more useful.

In this repo I found some documents but them seem old. I think we can reuse this repo to publish documents for NutsDB. I'm not quite sure what framework was used in the existing nutsdb-docs. Maybe we can perfect it or use some other framework like https://github.com/facebook/docusaurus . docusaurus has rich document functions and good supports for multiple versions, multiple languages, and also can publish blogs.

Totally, I think use a github page to present more rich documents will be better for promoting NutsDB.

[xujiajun]

@TremblingV5 Indeed, this project has not been maintained for a long time, resulting in a lot of information being out of date. Currently, it is all markdown files. It seems that the static page is generated using https://jekyllrb.com/. I think your suggestion is very good.