Product core values in the docs

https://gitlab.com/gitlab-org/gitlab-ce/issues/35649 discussed the banners we show throughout GitLab and their usage rules. One of the outcomes was adding these guidelines to the Product handbook page (specifically, in the Product Core Values section): https://about.gitlab.com/handbook/product/#banners

As a parallel, the UX Guide details the usage of many other components (where “banners” would fit as well).

I believe the Product Core Values section in the Product handbook page and the UX Guide share the same intentions and possibly the same content. This goes to show that both Product and UX team have a lot in common and share responsibilities in defining the user experience of the product. However, the guidelines produced by these teams should be followed not only by GitLabbers, but everyone who contributes.

I always understood the documentation target audiences as:

• The Handbook for GitLabbers
• The Development docs and CONTRIBUTING.md for every contributor
• PROCESS.md for Core team members and GitLabbers

For that reason, it makes sense to move the Product Core Values section of the Product handbook page to the Development docs or similar.