Handle dual-license repos

[MiWeiss]

Github can detect dual-licensed repos (in some cases), yet licenseplate does not show info for these yet.

Example: https://github.com/arnavyc/dual-licensed-mit-apache

We must change licenseplate to indicate dual license. The color of the alertbar should be the one of the "more permissive" one. No license details (permissions, ...) should be shown in the extended alertbar, instead there should be all links to the found licenses on choosealicense.com