Add support for customizable database types for transport_maps, recip…

[tobias-richter]

…ient_canonical_maps, sender_canonical_maps

I introduced

• postfix_sender_canonical_maps_database_type
• postfix_recipient_canonical_maps_database_type and
• postfix_transport_maps_database_type

in order to be able to customize these database types in detail.

[tersmitten]

Looks like a nice addition. I think that you also need to make changes in handlers/main.yml. Can you have a look?

[tobias-richter]

@tersmitten you are totally right, I overlooked that part. This also explaines some strange issues I was experiencing. This is now adjusted.

[tersmitten]

Also see #90

[tobias-richter]

Yes, I saw this PR just after I created mine. But there is no activity at the moment. Should I adjust my PR to also contain the changes from #90?