Try downloading pinot's deps as maven instead of unpacking shaded jars

[codefromthecrypt]

In our kafka image, there's an example of getting deps from maven. Right now, we are unpacking shaded jars as at runtime they are slower to boot. It is possible that a directory full of natural jars are as fast or similar to unpacking classes at runtime. For example, Kafka is pretty quick coming up without needing to resort to unpacking jars into a big folder (which costs image size).

This depends on a change at pinot to make their poms usable, and likely use of jitpack repository to get a git hash until a stable milestone of pinot 0.5 is released

apache/pinot#5945