postfix: refactor role

postfix/defaults/main.yml

postfix/files/login_maps.pcre

postfix/files/sender_login_map.hash

postfix/tasks/main.yml

postfix/templates/aliases.j2

postfix/templates/login_maps.pcre.j2

postfix/templates/mailname.j2

postfix/templates/main.cf.j2

postfix/templates/master.cf.j2

postfix/templates/postscreen_access.cidr.j2

postfix/templates/postscreen_cache.j2

postfix/templates/virtual.j2