Better handling of unencrypted connection to database

[chalkos]

Description: Fallback to unencrypted connection to database occurs when the connection fails. In some cases this might not be desirable.

Current default behaviour is:

1. Try to connect to database using encrypted connection
2. If the above failed, try to connect to database using unencrypted connection
3. If the above failed, abort, because no connection is possible

To solve this issue provide a way for the user to specify the following behaviour:

1. Try to connect to database using encrypted connection
2. If the above failed, abort, because no encrypted connection is possible