Changes:
* This removes MSBuild targets which invoke `docker` commands to build
deb and rpm installers
* Remove installer targets from the KoreBuild context. Put them into
separate project files
* Simplify the targets used to build installers by reducing duplicate
variable names and deeply nested MSBuild contexts
* Remove unused dependencies from the Docker build context
For reasons I don't understand, curl started failing over the weekend with:
curl: (48) An unknown option was passed in to libcurl
This change to wget instead which works just as well