Provide JDK type conversions

As a user of the configuration API and/or injection mechanisms, I expect there to be a range of default value type conversions so that I can have configuration values of common JDK value types without having to explicitly enable or implement those conversions.
Source: https://github.com/eclipse-ee4j/config/discussions/27#discussioncomment-1809272

Start by reading the linked discussion and then inspect the configuration API and injection mechanisms mentioned in the issue. Done means common JDK value types can be used as configuration values without explicitly enabling or implementing conversions.

Written by the indexing model from the issue text.