feat(experiences): add separate banner component

[Haroenv]

Summary

adds a separate banner "widget" (uses connectHits) and ensures banner doesn't show inside hits

Result

FX-3002

[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 7987eb8:

Sandbox	Source
example-instantsearch-getting-started	Configuration
example-react-instantsearch-getting-started	Configuration
example-react-instantsearch-next-app-dir-example	Configuration
example-react-instantsearch-next-routing-example	Configuration
example-vue-instantsearch-getting-started	Configuration

[dhayab]

This implementation doesn't read from renderingContent.widgets.banner but instead relies on an explicit banner block, is that right?

[Haroenv]

@dhayab it reads from renderingContent still, but is a separate widget from the hits widget

[dhayab]

Oh I misread it, I see now it uses connectHits as the basis as well. Good for me then!