move external components to their own files (#319)

* move ldap to its own file
* add separate files for db and mail as well
* add new compose file to the default compose_file variable
* enhance setup.sh to add these new compose files if they are currently missing

docker-compose.ports.yml

@@ -7,16 +7,6 @@ services:
       - "${HTTP:-80}:80"
       - "${HTTPS:-443}:443"
 
-  ldap:
-    ports:
-      - ${LDAPPORT:-389}:389
-
-  mail:
-    ports:
-      - "${SMTPPORT:-25}:25"
-      - "${SMTPSPORT:-465}:465"
-      - "${MSAPORT:-587}:587"
-
   kopano_server:
     ports:
       - ${KOPANOPORT:-236}:236