expose conversion mechanism in API

There are certain cases where a user of microprofile-config might want to convert a supplied string into different type using the same mechanism as a resolved property value. For example, when a fallback value for a particular usage point is available from a string supplier, but not appropriate to contribute as a formal config source.

I suggest adding the following method to org.eclipse.microprofile.config.Config:

<T> T convert(String value, Class<T> type);

[Emily-Jiang]

@emattheis If you check the due date on milestone, you will find out the target date. The release train is departing. As for last year, we spent a lot of time discussing dynamic aspect of Config and created APIs. However, this is a great fit for Quarkus, which is static. We then undid a lot of stuff. We now take everyone onboard and align with each other. As @radcortez said, we will get the Config 1.4 out and then discuss what we want to focus on 2.0 so that we won’t run into the same issue as last year. I understand your frustration. Hope we can move along faster after 1.4 release!

[radcortez]

I agree that at this time it is hard to include additional features to 1.4. Considering the amount of discussion and back and forward with the null issue, I see that this particular one going on the same path and unfortunately there is no time for it if we want to get something out.

I also agree that we need to have a more clear roadmap, so contributors are aware of the release plan so they are able to push and advocate for the features they need to be included in the release cycle.