add feature to use only one key for many servers and some improvements

templates/exclude.list.j2

@@ -1,21 +1,8 @@
-/var/lib/bareos
-/dev
-/media
-/mnt
-/proc
-/sys
-/tmp
-/var/cache
-/var/tmp
-/var/lib/mongodb
-/var/lib/mysql
-/var/lib/postgresql
-/var/lib/redis
-/var/lib/solr
-/var/lib/elasticsearch
-/var/spool/postfix
-/var/www
-/VMs
-/.journal
-/.fsck
-/zpve
+{% for exclude in duplicity_list -%}
+{{ exclude }}
+{% endfor %}
+{% if duplicity_list_custom is iterable %}
+{% for exclude in duplicity_list_custom -%}
+{{ exclude }}
+{% endfor %}
+{% endif %}