Add support for parsing codemeta.json files.

[pombredanne]

Codemeta is a spec for code metadata https://codemeta.github.io/
We could treat this as package data and collect them in packagedcode.

See for example

• https://github.com/search?l=&p=5&q=codemeta+filename%3Acodemeta.json&ref=advsearch&type=Code
• https://github.com/indigo-dc/udocker/blob/master/codemeta.json

[KaiDevrim]

Hi! I would like to take this issue as part of a CodeDay team!