First version of a CatchallAlias class
I based the CatchallAlias class in catchall.py heavily on the Alias class, but
by copy, not deriving. The two are functionally related, but the
implementations are too different because CatchallAliases have no localpart.
# All parameters are described in pgsql_table(5) / PGSQL PARAMETERS
#
# The hosts that Postfix will try to connect to and query from.
hosts = localhost
# The user name and password to log into the pgsql server.
user = postfix
password = some_password
# The database name on the servers.
dbname = mailsys
# The SQL query template used to search the database
query = SELECT destination FROM postfix_virtual_alias_map('%u', '%d')