Canonical license format with support for aliases

[thomasdarimont]

To ease scanning of licenses for different platforms and dependencies it would make sense
to be able to have a uniform representation of license (names).

Since some platforms use different identifier to express the same license it would be helpful to have
a mapping from canonical license names to (platform / dependency manager specific) aliases.

Examples could look like:

licenses:
  - canonicalName: "apache_v2"
    aliases: ["Apache*", "Apache-2.0", "Apache 2.0"]