Addon-docs: Extract ArgType parameters by component

[shilman]

#10373 intended to reduce the data sent over the channel on app startup by "normalizing" story parameters (e.g. sending component-level parameters once per component rather than once per story).

It appears that component ArgTypes are being sent per-story rather than per-component, thus losing out on a performance opportunity. Need to fix the argTypes extractor to do the right thing.

[shilman]

@tmeasday this requires:

• a protocol for enhancers to know whether they are being called on component/kind parameters or story parameters
• enhancers to be updated to support this protocol
• story store to be updated to support the protocol and to call the enhancers on kind parameters

Pretty sure I'd come up with a plan when we did the normalization work, but none of that is implemented AFAICT and it seems like a bigger task than I'd thought. WDYT?

[tmeasday]

Sounds about right! I'm not sure how hard it is to update the individual enhancers @shilman but if we decide on the API the store part will be quick I think.

[matheo]

@tmeasday I've highlighted all the extractors in this PR: https://github.com/storybookjs/storybook/pull/11068/files

In the code, I only see one enhanceArgTypes in docs/frameworks/common
and I'm assuming that's the one to be called once by component @shilman?

[shilman]

Won't fix. On-demand architecture fixes plus we're moving to annotations server in the future.