Document using Alpine Linux for development

[jwoertink]

Ref: https://github.com/luckyframework/lucky/pull/1517#pullrequestreview-676818765

There's a few issues currently because of how slim Alpine is. We can add a whole guide around setting it up, and installing all of the dependencies.

[matthewmcgarvey]

https://github.com/luckyframework/lucky/issues/1255