ejabberd: Make some limits configurable

ejabberd/templates/ejabberd.yml.erb

@@ -141,7 +141,7 @@ access:
     admin: 1000
     all: 100
   max_user_sessions:
-    all: 1000
+    all: <%= @max_user_sessions %>
   muc:
     local: allow
   muc_admin:
@@ -180,8 +180,8 @@ modules:
     access_create: muc_create
     access_persistent: muc_create
     history_size: 100
-    max_users: 1000
-    max_user_conferences: 2000
+    max_users: <%= @muc_max_users %>
+    max_user_conferences: <%= @max_user_conferences %>
     default_room_options:
       allow_user_invites: true
       anonymous: false
@@ -190,7 +190,7 @@ modules:
 <% else -%>
       logging: false
 <% end -%>
-      max_users: 1000
+      max_users: <%= @muc_max_users %>
       members_by_default: false
       members_only: true
       public: false