File format parsing

[puria]

When a file is read could be verbatim, or... can be in a specific format:

• .yml
• .json
• .base64
• .zen

I'm in doubt to allow to parse them directly in the fs package. By now the json is parsed directly.

Maybe I would prefer to have specific packages for the different formats and leave the fs to do read from a file and put the outcome into a string, and then in the following sentence for each format we can have a pkg for parsing the format.