Rename 'macros.j2' to avoid it in with_fileglob
Refactor Postfix hash tables

Hash tables generated by 'postmap' and 'postalias' commands are now in
separate directories.

Makefiles used to generate them manage all *.in files in
their current directory, instead of using static lists written by
Ansible. This allows to create custom hash tables by other Ansible roles
in specific directories and by using 'debops.postfix' role as
a dependency, generate hash tables via handlers.
Remove static lists of templates

Because of refactoring of Makefiles, we don't need to use static lists
of templates to generate the tables. Instead, all *.j2 templates from
specified directory are selected via 'with_fileglob' and processed.
Merge pull request #14 from drybjed/refactor-postfix-tables

Refactor Postfix hash table management