Static haskell build in alpine container with musl

## To build demo

 1. ./mkDocker.sh 
 1. cd egProject
 1. stack --docker build

ldd on the resulting binary will show static binary


## Based on

 - https://www.reddit.com/r/haskell/comments/bxggkz/ghc_builds_for_alpine_linux/
 - https://github.com/jkachmar/alpine-haskell-stack/blob/master/Dockerfile

## Notes

 - stack.yaml
   - `repo: "apline_hs_8_6_5:latest"` so that stack uses the correct container
   - `stack-exe: image` use stack from the image not the host

 - .cabal
   - `ghc-options: -static -optc-static -optl-static -fPIC ...`
   - `ld-options: -static`