[feat] Create `<rh-textarea>` component/pattern

[kelsS]

Description

We need a <textarea> component that allows us to have a multiline user input area in a form. It needs to have the proper form labelling and possibly a way for updating the aria-labelling by the implementor to fit the context of their form.

We have been encouraged to work on AI apps and in doing so we will need form elements that face the end user (in this case - RH workers I assume) that need to be properly accessible and branded.

Acceptance Criteria

• Design done
• Development done

Images

I have no design, I just know we need this and other form elements in the RHDS.

Design file

No response

Other resources

https://www.w3.org/WAI/tutorials/forms/

Thanks for looking into this!

[coreyvickery]

@kelsS @markcaron Do we want to use this issue to redesign all form inputs in light and dark color schemes? I think Marionne and I have already started some of that work because the Docs dot team is requesting.

[markcaron]

@coreyvickery yes. We should be about ready to tackle form elements, though fair warning: cross-root ARIA issues still exist in Web Components.