Copy properties instead of setting as default value

[rPraml]

When you define

final var props = new Properties(connectionProps);
props.setProperty("user", username);
props.setProperty("password", password);

and use the Map interface, e.g. props.keySet() will return exactly user and password

Only a direct access with property.getValue("someVal") will fall through to connectionProps

Unfortunately some drivers like H2 and also MariaDB use the Map interface of Properties, which does not expose the underlying default values.

I noticed this, as some custom connection properties were not correctly applied to the driver.

So the use of Properties(defaults) can be a trap.
This PR changes all places to copy the defaults to the new object.

@rbygrave this is IMHO a low hanging fruit ;)