Attempt to convert log4j configuration into dropwizard logging configuration.

If a log4j configuration exists, convert it into yaml appropriate for a Dropwizard config.

We do this because the way we run our Dropwizard app is non-standard (going through `BluefloodServiceStarter` instead of invoking the main method in `IngestApplication`.

If we did not do this, BF code would still log as expected, but all the DW classes would log with default settings.

This isn't about logback vs log4j vs anything else.

Only handles FileAppender and ConsoleAppender right now.