Fill out v1.9 remaining docs

[markerikson]

This PR:

• Updates Yarn to 3.2.4, as 3.1.0 didn't want to install an updated Docusaurus properly
• Updates Docusaurus to 2.1.0
• Exports defaultSerializeQueryArgs for now
• Documents the new RTKQ endpoint fields
• Documents the new fetchBaseQuery args and reworks that page in general
• Adds a page for "Codemods"

Fixes #2619 , or will once I'm done with it.

I'm most likely going to move the defaultSerializeQueryArgs export to its own branch, and also see about changing the serializeQueryArgs endpoint option to let you just return a non-string value if you want, but put it here for now because I needed to show an example of how serializeQueryArgs works now and realized we don't export that.

[codesandbox]

  Open in CodeSandbox Web Editor | VS Code | VS Code Insiders

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 6763f7b:

Sandbox	Source
Vanilla	Configuration
Vanilla Typescript	Configuration
rsk-github-issues-example	Configuration
@examples-query-react/basic	Configuration
@examples-query-react/advanced	Configuration
@examples-action-listener/counter	Configuration

[ggaabe]

If the value being upserted is undefined, will it remove the cache key entirely? If not, is there a way to remove a cache entry entirely? (ie, like invalidateTags, but without triggering a refetch)

[markerikson]

@ggaabe : no, it would replace the .data field with undefined. It's the value, not the key.

There isn't currently a way to remove one, but a few folks have asked for something like this. Could you comment over in #2820 and describe when and why you might want to do that?

[markerikson]

Docs should be updated, pending me figuring out what to do with the defaultSerializeQueryArgs thing

[markerikson]

Odd, no PR preview.

We'll, let's get it in.