CHAOSS metrics/indicators

[dgarijo]

Many have been defined already! See https://chaoss.community/kbtopic/software/
We should add the appropriate source if we use them in EVERSE.

[dgarijo]

Also, the "objectives" or "purpose" field is something we can add in our metadata schema.
I am less inclined to include the tools including it, as we would need to be constantly updating the metric to see the support by tools