Consider adding mapping to the Package class for related Packages

[johnmhoran]

Some Packages have changed their namespace over time. One example is pkg:maven/log4j/log4j@1.2, where (if I understand the progression) the 2.x versions have a different namespace, e.g., pkg:maven/org.apache.logging.log4j/log4j@2.0. (I think this GitHub repo is related to this relationship.)

It would be useful to create a mapping for these Packages, perhaps in the Package class, so that a query for the fixed versions of a potentially affected Package will return all relevant namespaces for that Package.

[johnmhoran]

See also aboutcode-org/purldb#175