Refactor postfix::sasl_auth and send_dependent_relayhosts
Refactor postfix::sasl_auth and send_dependent_relayhosts

- Recipe is run automatically if smtp_sasl_passwords is set
- Default smtp_sasl_password_maps value provided so you don't have to
  manually set it

Similarly, add default sender_dependent_relayhost_maps so you don't
have to manually set it

btquanto/chef-cookbooks,btquanto/chef-cookbooks,pli888/chef-cookbooks,williamnhan/chef-cookbook-test,cogini/chef-cookbooks,pli888/chef-cookbooks,cogini/chef-cookbooks,pli888/chef-cookbooks,btquanto/chef-cookbooks,btquanto/chef-cookbooks,williamnhan/chef-cookbook-test,pli888/chef-cookbooks,phunehehe/chef-cookbooks,phunehehe/chef-cookbooks,pli888/chef-cookbooks,phunehehe/chef-cookbooks,williamnhan/chef-cookbook-test,cogini/chef-cookbooks,btquanto/chef-cookbooks,williamnhan/chef-cookbook-test,phunehehe/chef-cookbooks,cogini/chef-cookbooks,phunehehe/chef-cookbooks,williamnhan/chef-cookbook-test,cogini/chef-cookbooks