Split out the context for ConfigProvider as a package for supporting dynamic-import via esmodule server

[Justinidlerz]

What problem does this feature solve?

For the bundle-less case, we will use import('https://some.cnd.com/antd/es/${componentName}') to import the needed components.
But many dependencies loaded via the network will slow down the page speed (waterfall).
Such as load a button component must run the flow to download dependencies:
button.js -> button-group.js -> LoadingIcon.js -> etc... and another outside-of-the-button package dependencies

To prevent the above problem, we bundle each component package, see like: import('https://some.cnd.com/antd/es/${componentName}?bundle')
And the download will be reduced to button.bundle.js and another outside-of-the-button package dependencies

When needs to config some global settings using the ConfigProvider, the context will be bundled into the config-provider.bundle.js file, so the button component will not import the same context file with the config-provider.

What does the proposed API look like?

The feature hasn't changed API, But needs to modify the packages structure:
Origin structure:

- | components
------ | config-provider
-------------- | context.ts
-------------- | index.ts

New structure:

- | components
------ | config-provider
-------------- | index.ts 
------ | context
-------------- | index.ts 

And the bundled es module will see like:

- | es
------ | config-provider
-------------- | index.js 
------ | context
-------------- | index.js 

And the browser will download the same context/inde.bundle.js file to share the React's context to solve the problem.