Add deb package and nightly distribution (#1977)

- Add publishing automated debian package releases via Cloudsmith.io, which allows evcc to be installed and updated via `apt`
- Add nightly docker (:latest) and deb distribution
- Disable docker builds for every commit on master
- Allow nightly builds to be triggered manually

packaging/scripts/preremove.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+set -e
+
+if [ -d /run/systemd/system ] && [ "$1" = remove ]; then
+	deb-systemd-invoke stop evcc.service >/dev/null || true
+fi