Corrected a number of apt packaging issues

debian/postinst

@@ -4,7 +4,8 @@ set -e
 
 id -u reminder &>/dev/null || useradd -r -M reminder
 
-if [ ! -f /etc/reminder-rs/config.env ]; then
+if [ ! -f '/etc/reminder-rs/config.env' ]; then
+  echo "Copying configuration file..."
   cp /etc/reminder-rs/default.env /etc/reminder-rs/config.env
 fi
 

debian/postrm

@@ -1,11 +0,0 @@
-#!/bin/bash
-
-set -e
-
-id -u reminder &>/dev/null || userdel reminder
-
-if [ -f /etc/reminder-rs/config.env ]; then
-  rm /etc/reminder-rs/config.env
-fi
-
-#DEBHELPER#