[Proposal] Pivot to Markdown as universal file format

[erikhofer]

Advantages:

• Items can be browsed on Sites like GitHub and GitLab as is
• Editing of files outside of scope42 can be done with any Markdown editor
• markdownlint can be applied easily
• Enables Markdown processing with things like remark

Disadvantages:

• Parsing is harder to implement and propably needs to become more tolerant
• Files can not be processed with simple YAML tooling anymore, it basically can only be done with our libraries, if you need the model
• [Proposal] Improve file names #29 would become impossible because it would break links
• This is not sufficient for exporting. The Markdown needs to be processed if things like scripting are used.

Additional considerations

• We may want to stick with YAML for a 1.0.0 and decide on this later. An automatic migration is trivial because we need Model->Markdown serializer anyways.

[erikhofer]

Files can not be processed with simple YAML tooling anymore, it basically can only be done with our libraries, if you need the model

I think this is the major blocker here. We cannot implement parsers in every programming language. This would make the structured data basically unaccessible for most people.

The only option I think is feasble is Markdown for the item description and YAML frontmatter for everything else. This is, however, not useful for all item types. For example, decisions are basically only structured data and currently don't even have a "description".

[erikhofer]

Another idea: Split items into multiple files to avoid nested frontmatters, e.g. a file for each comment.

Also, instead of pivoting completely, we could support both formats and give the users the choice which one to use.