chasquid-util: Make the commands more user-friendly

This patch changes chasquid-util's subcommands and parameters to
(hopefully) make them more user friendly and intuitive by default.

The changes include defaulting the configuration to /etc/chasquid, and
using full addresses as usernames.

It also adds some shell tests to cover most of the functionality.

cmd/chasquid-util/test.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+
+set -e
+. $(dirname ${0})/../../test/util/lib.sh
+
+init
+
+go build || exit 1
+
+function r() {
+	./chasquid-util -C .config "$@"
+}
+
+function check_userdb() {
+	if ! r check-userdb domain > /dev/null; then
+		echo check-userdb failed
+		exit 1
+	fi
+}
+
+
+mkdir -p .config/domains/domain
+touch .config/chasquid.conf
+
+if ! r print-config > /dev/null; then
+	echo print-config failed
+	exit 1
+fi
+
+if ! r user-add user@domain --password=passwd > /dev/null; then
+	echo user-add failed
+	exit 1
+fi
+check_userdb
+
+if ! r authenticate user@domain --password=passwd > /dev/null; then
+	echo authenticate failed
+	exit 1
+fi
+
+if r authenticate user@domain --password=abcd > /dev/null; then
+	echo authenticate with bad password worked
+	exit 1
+fi
+
+if ! r user-remove user@domain > /dev/null; then
+	echo user-remove failed
+	exit 1
+fi
+check_userdb
+
+if r authenticate user@domain --password=passwd > /dev/null; then
+	echo authenticate for removed user worked
+	exit 1
+fi
+
+echo "alias: user@somewhere" > .config/domains/domain/aliases
+A=$(r aliases-resolve alias@domain | grep somewhere)
+if [ "$A" != "(email)  user@somewhere" ]; then
+	echo aliases-resolve failed
+	echo output: "$A"
+	exit 1
+fi
+
+C=$(r print-config | grep hostname)
+if [ "$C" != "hostname: \"$HOSTNAME\"" ]; then
+	echo print-config failed
+	echo output: "$C"
+	exit 1
+fi
+
+success