Refactor makefile, add ubuntu1804 and fix label bug

[stolsma]

Add Ubuntu 18.04 as checked base image. Refactor build, push and export steps Fix label bug where label data with comma is truncated

Signed-off-by: stolsma [email protected]

[mestery]

Ubuntu 18.04 Bionic Beaver will be supported until April of 2023. Not sure we really want to add support for it here. What do you think @stolsma?

[stolsma]

If we don't do support we also have to remove all the 18.04 specific build scripting IMHO. I don't think we are that far to decide on that, so that's why I added it to the CI build step. Then we at least will know when 18.04 doesn't work.... Also its only one reference to add at the moment so no big deal to add😉

[stolsma]

Btw it should be ready for review after this last running check (I removed some debugging lines...)