Add ldap auth for postfix and dovecot (#352)

* Add ldap support for postfix and dovecot

* Add SASLAUTHD

* Update README.md

* Add necessary packages to dockerfile

* Add config files for ldap

* Add tests for ldap auth

test/docker-openldap/bootstrap/ldif/01_mail-tree.ldif

@@ -0,0 +1,5 @@
+dn: ou=people,dc=localhost,dc=localdomain
+changetype: add
+objectClass: organizationalUnit
+objectClass: top
+ou: people

test/docker-openldap/bootstrap/ldif/02_user-email.ldif

@@ -0,0 +1,25 @@
+# -------------------------------------------------------------------- 
+# Create mail accounts
+# -------------------------------------------------------------------- 
+# Some User
+dn: uniqueIdentifier=some.user,ou=people,dc=localhost,dc=localdomain
+changetype: add
+objectClass: organizationalPerson
+objectClass: person
+objectClass: top
+objectClass: PostfixBookMailAccount
+objectClass: extensibleObject
+cn: Some User
+givenName: User
+mail: some.user@localhost.localdomain
+mailAlias: postmaster@localhost.localdomain
+mailGroupMember: employees@localhost.localdomain 
+mailEnabled: TRUE
+mailGidNumber: 5000
+mailHomeDirectory: /var/mail/localhost.localdomain/some.user/
+mailQuota: 10240
+mailStorageDirectory: maildir:/var/mail/localhost.localdomain/some.user/
+mailUidNumber: 5000
+sn: Some
+uniqueIdentifier: some.user
+userPassword: {SSHA}eLtqGpid+hkSVhxvsdTPztv4uapRofGx

test/docker-openldap/bootstrap/schema/mmc/postfix-book.schema

@@ -0,0 +1,70 @@
+# $Id$
+#
+# State of Mind
+# Private Enterprise Number: 29426
+#
+# OID prefix: 1.3.6.1.4.1.29426
+#
+# Attributes: 1.3.6.1.4.1.29426.1.10.x
+#
+
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.1 NAME 'mailHomeDirectory'
+	DESC 'The absolute path to the mail user home directory'
+        EQUALITY caseExactIA5Match
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.2 NAME 'mailAlias'
+        DESC 'RFC822 Mailbox - mail alias'
+        EQUALITY caseIgnoreIA5Match
+        SUBSTR caseIgnoreIA5SubstringsMatch
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.26{256} )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.3 NAME 'mailUidNumber'
+        DESC 'UID required to access the mailbox'
+        EQUALITY integerMatch
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.4 NAME 'mailGidNumber'
+        DESC 'GID required to access the mailbox'
+        EQUALITY integerMatch
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 SINGLE-VALUE )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.5 NAME 'mailEnabled'
+	DESC 'TRUE to enable, FALSE to disable account'
+        EQUALITY booleanMatch
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 SINGLE-VALUE )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.6 NAME 'mailGroupMember'
+	DESC 'Name of a mail distribution list'
+        EQUALITY caseExactIA5Match
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.7 NAME 'mailQuota'
+	DESC 'Mail quota limit in kilobytes'
+        EQUALITY caseExactIA5Match
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )
+
+attributetype ( 1.3.6.1.4.1.29426.1.10.8 NAME 'mailStorageDirectory'
+	DESC 'The absolute path to the mail users mailbox'
+        EQUALITY caseExactIA5Match
+        SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 SINGLE-VALUE )
+
+
+#
+# Objects: 1.3.6.1.4.1.29426.1.2.2.x
+#
+
+objectclass ( 1.3.6.1.4.1.29426.1.2.2.1 NAME 'PostfixBookMailAccount'
+        SUP top AUXILIARY
+	DESC 'Mail account used in Postfix Book'
+	MUST ( mail )
+        MAY ( mailHomeDirectory $ mailAlias $ mailGroupMember 
+		$ mailUidNumber $ mailGidNumber $ mailEnabled
+		$ mailQuota $mailStorageDirectory ) )
+
+objectclass ( 1.3.6.1.4.1.29426.1.2.2.2 NAME 'PostfixBookMailForward'
+        SUP top AUXILIARY
+	DESC 'Mail forward used in Postfix Book'
+	MUST ( mail $ mailAlias ))
+