Separate and publish icons to different packages to keep versions of icons

[wmira]

The problem at the moment with having a single version is that if we decided to upgrade an icon-set and that icon changes for some reason, the current icon being used by a user changes as well. So now people migrating to 2.x for example would be seeing a very different material design icons. We should separate the build to core, icon-packages such that it is possible to upgrade the core but leave the version for the given icon set unchanged if needed.