Fill in content for additional resources tab

[abbycross]

Closes #1698

[abbycross]

I see that when you click on the contributor or corporate license agreements items in the left nav, PDF files automatically open up outside the browser. Is there an icon we can use in the left nav to indicate that? A download icon or at least the external link one? What do you think @Eric-Arellano @gracelindsell

[Eric-Arellano]

(Ik it's a wip - pardon if you already knew this feedback)

FYI I've asked Luciano if he can write 1-2 paragraphs for open-source/index.mdx. We'll also need metadata for that file.

[Eric-Arellano]

Is there an icon we can use in the left nav to indicate that? A download icon or at least the external link one?

Yeah, I was hoping the external link icon (up-right arrow) would Just Work. I have to figure out how to get it to work. I'll open an issue in closed source.

[abbycross]

Since we aren't doing migration guides yet, I think the only piece missing is the content and metadata for the open-source intro file (and a review of this PR).

[qiskit-bot]

One or more of the following people are relevant to this code:

• @abbycross
• @beckykd
• @javabster
• @mtreinish

[abbycross]

I've moved the responsible-quantum-computing file into this PR to streamline efforts. @javabster approved that file in #1670

[Eric-Arellano]

Thanks! This is safe infra-wise to merge now. It won't go live yet.