Use awscli from Alpine

Python2 is no longer in the Alpine repos. Skip pip and just
use the awscli from Alpine, which is on Python 3.

Dockerfile

@@ -2,15 +2,10 @@ FROM alpine:3
 
 RUN apk -v --update add \
         bash \
-        python \
+        aws-cli  \
-        py-pip \
-        groff \
-        less \
-        mailcap \
         jq \
         wget \
         && \
-    pip install --upgrade awscli==1.14.5 s3cmd==2.0.1 python-magic && \
     apk -v --purge del py-pip && \
     rm /var/cache/apk/*