Refactor: Dockerimage (#5007)

* refactor docker image to reduce size

* Added required deps for database drivers

* Added alpine test dockerfile

* Readded image libs to Dockerfile

* Fix link in dockerfile

* Replaced Dockerfile

* Remove bash from image

* Added base target to Dockerfile

* Added missing mysql dev headers

* Add dev target back to Dockerfile

* fix: Dockerfile style

* Add old comments back to dockerfile

* Removed wrong comment

* Added back piwheels repo

docker/init.sh

@@ -1,9 +1,11 @@
-#!/bin/bash
+#!/bin/sh
 # exit when any command fails
 set -e
 
 # Required to suppress some git errors further down the line
-git config --global --add safe.directory /home/***
+if command -v git &> /dev/null; then
+    git config --global --add safe.directory /home/***
+fi
 
 # Create required directory structure (if it does not already exist)
 if [[ ! -d "$INVENTREE_STATIC_ROOT" ]]; then