Find way to allow shared-doc content to use shortcodes

[chalin]

Originally posted by @chalin in #3931 (comment)

We should explore ways to be able to use shortcodes here (most likely in a template).

[svrnm]

to be honest I am not happy with the way how we use shortcodes as "shared-doc", this is especially also with the localizations leading to additional complexity. It would be great if we could find a better approach, e.g. some kind of "content templates" that can be merged into a site but still live in the content/<language>/ folder so they are also easy to find for folks doing the translations.

As of today hugo seems not to have a good solution for that, the things I am aware of are:

• shortcodes (what we do today)
• localization files (not sure how much markdown we can use within those strings)
• some readFile magic