Standarize image by using shared / similair layers

optional/clamav/Dockerfile

@@ -1,5 +1,9 @@
-FROM python:3-alpine
-
+FROM alpine:3.8
+# python3 shared with most images
+RUN apk add --no-cache \
+    python3 py3-pip \
+  && pip3 install --upgrade pip
+# Image specific layers under this line
 RUN apk add --no-cache clamav rsyslog wget clamav-libunrar
 
 COPY conf /etc/clamav

optional/clamav/start.py

@@ -1,4 +1,4 @@
-#!/usr/local/bin/python3
+#!/usr/bin/python3
 
 import os
 
@@ -9,4 +9,4 @@ os.system("[ -f /data/main.cvd ] || freshclam")
 os.system("freshclam -d -c 6")
 
 # Run clamav
-os.system("clamd")
+os.system("clamd")