Remove Travis CI config

Create Github Actions config
Split tox ini into one per supported distro so they can be run seperately

Signed-off-by: Adam Warner <me@adamwarner.co.uk>

test/_debian_9.Dockerfile

@@ -0,0 +1,16 @@
+FROM buildpack-deps:stretch-scm
+
+ENV GITDIR /etc/.pihole
+ENV SCRIPTDIR /opt/pihole
+
+RUN mkdir -p $GITDIR $SCRIPTDIR /etc/pihole
+ADD . $GITDIR
+RUN cp $GITDIR/advanced/Scripts/*.sh $GITDIR/gravity.sh $GITDIR/pihole $GITDIR/automated\ install/*.sh $SCRIPTDIR/
+ENV PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:$SCRIPTDIR
+
+RUN true && \
+    chmod +x $SCRIPTDIR/*
+
+ENV PH_TEST true
+
+#sed '/# Start the installer/Q' /opt/pihole/basic-install.sh > /opt/pihole/stub_basic-install.sh && \