move the trademark policy to terms.archlinux.org

Its old home was https://wiki.archlinux.org/title/DeveloperWiki:TrademarkPolicy and the text has only been changed with regard to formatting not content.

The goal of this change is to have all legal documents in once place.

fixes #5 (closed)

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ToDos:

• modify https://gitlab.archlinux.org/archlinux/service-agreements/-/blob/master/README.md
• modify external projects and set a redirect on the wiki
• announce the MR on a-d-p after its not a draft anymore (see !22 (comment 113652))
• announce the move on a-d-p