Add basic convertor of other formats to/from ORF

[MasterOdin]

I am writing this issue out to gain feedback, but I plan to put the work in for putting this together. @techhat please let me know what your preferred languages for this would be. I am assuming python given your usage of rST, but perhaps you've moved onto a different language.

It would be useful in adopting ORF to allow it to both input well-known formats and to output to them as well. While I might wish all existing sites made use of it, that's not the case, and so having interoperability with their formats is somewhat necessary.

http://microformats.org/wiki/recipe-formats provides a list of many formats. Some of these formats are read and so may just need the Format -> ORF and not vice versa.

My current planed list is:

• MealMaster
• Recipe Markup Language
• MasterCook
• https://schema.org/Recipe
• JSON-LD (https://github.com/techhat/openrecipeformat/issues/16#issuecomment-516233303)
• h-recipe
• paprika file format.

@techhat, let me know if you've got any formats you would like to see supported.

[shoeper]

There is an app called RecetteTek. Looks like they are using json. Don't know the format and whether there is a specification, though. Recipes can be generated using https://www.recettetek.com/en/generator