Check whether a file/project is open-source

[tdegueul]

Scava shall be able to check whether the license used by a file/project is open-source.

Services such as https://licenses.opendefinition.org/ shall come in handy, e.g.:

curl https://licenses.opendefinition.org/licenses/EPL-2.0.json

How do we want the result to be displayed to the user? As a metric? In the dashboard?