build: revert to using the default alpine based docker image

Build both standard and linuxserver based images.
linuxserver based images can be accessed by adding `-s6` suffix to the docker image name

docker_config.json

@@ -0,0 +1,8 @@
+{
+  "port": 80,
+  "baseURL": "",
+  "address": "",
+  "log": "stdout",
+  "database": "/database.db",
+  "root": "/srv"
+}