Add Excerpt component

[acelaya]

Part of hypothesis/h#9808

Extract Excerpt component from the client so that we can have collapsible annotation bodies and quotes in h moderation queue.

[acelaya]

Extracted from the client verbatim

[acelaya]

Extracted from the client, with the only difference that in there we inject the app settings i order to resolve the inline control styles.

In here I removed any reference to the settings and added a new inlineControlsLinkStyle optional prop that serves the same purpose.

[acelaya]

I brought this utility from the client, and left it as an unexposed internal hook, because it is currently used only by the Excerpt component.

However, it is referenced in a comment inside another component, as something that could be potentially used there.

We may want to eventually expose it from here, or just duplicate the code, since it's not a huge piece of logic.

[robertknight]

This utility was originally written before ResizeObserver existed, so it had a more complex implementation. With the current implementation, the code might come out better if you just used ResizeObserver directly in the calling component.

[acelaya]

I think I'll keep it for now, to avoid having to refactor the Excerpt tests where observeElementSize is currently mocked.

I'll create an issue to simplify this separately.

[robertknight]

LGTM. I noted that the code might be simplified by removing observeElementSize and just using ResizeObserver directly. That utility was originally more complex because it was created before ResizeObserver support became ubiquitous.

[robertknight]

This utility was originally written before ResizeObserver existed, so it had a more complex implementation. With the current implementation, the code might come out better if you just used ResizeObserver directly in the calling component.