Alpine images

[amenzhinsky]

Hi there.

I would be nice if we had golang-alpine based images, since it has some advantages over debian based ones in terms of CI/CD, like total image size and apk is way faster than apt when it's needed to install something within a pipeline. Besides many people use alpine to build their code.

[jirfag]

Hi! It's a good idea, pull requests are welcome.

[tpounds]

Relates to #528.