Define our core code base

Originally created by @hefee on #16531 (Redmine)

To be able to prioritize better etc. We should have a list of supported applications and workflows, maybe also connected to personas. Publish this also on the website.

Related issues

• Related to #8310 (closed)
• Related to #16477 (closed)
• Related to #17183 (closed)
• Related to #17169 (closed)
• Related to #15816 (closed)
• Blocks #12264 (closed)