Add codemeta.json based on pom.xml

[salvafern]

Hello there :wave: I have generated a codemeta file based on pom.xml using codemetapy as

$ codemetapy pom.xml > codemeta.json

We are using codemeta files in the Jerico project. I figured I would PR in case this is useful for anyone else. If you find it interesting maybe we can include the generation of codemeta.json in the CI/CD pipeline.

Best regards, Salva