Add Digital Product Policy tab landing page + Data CoC

[egrace479]

Adds a landing page for the Digital Product Policy tab, providing context for the Imageomics Digital Products Release and Licensing Policy and Data Code of Conduct. The latter (Data CoC) is also newly included with this PR.

Resolves #57.

[hlapp]

I'm wondering whether we shouldn't just call this tab (and thus "section") simply Policies (and then in the intro paragraph adjust the text to not unintentionally suggest that these are all the policies we have).

Calling it Digital policies is a little confusing, because the policies here by definition are in digital form (= documents stored and served online), and it suggests that there are also policies that aren't digital (e.g., on paper, or stone tablets 😉).

In Digital Product and Release Policy the adjective works properly, because it really does talk about digital products only. (It just so happens that we don't create hardware products.)

[egrace479]

I'm wondering whether we shouldn't just call this tab (and thus "section") simply Policies (and then in the intro paragraph adjust the text to not unintentionally suggest that these are all the policies we have).

Calling it Digital policies is a little confusing, because the policies here by definition are in digital form (= documents stored and served online), and it suggests that there are also policies that aren't digital (e.g., on paper, or stone tablets 😉).

In Digital Product and Release Policy the adjective works properly, because it really does talk about digital products only. (It just so happens that we don't create hardware products.)

Based on our discussion about where this fits, I renamed Data Code of Conduct to Digital Product Life Cycle to fit better and set the about page to include the word "Product". Adjusted mkdocs.yaml and the page's associated images folder to match.

[hlapp]

🎉