Enable support to find protobin files from jars

[krmahadevan]

The current implementation of this library basically expects to find the .protobin in the file system. This is fine if the number of proto files are less, but when this count starts increasing the code generator which translates .proto to .java basically takes a lot of time and as such one would want these to be part of a separate Maven/Gradle module, which comes in as a dependency.

Now the problem here is that karate-grpc is not aware of the .protobin that can be embedded in the proto jar.

I have solved this in an internal fork of this codebase, but I was wondering if you are open to basically accomodating that here so that I dont have to maintain my own copy.

@thinkerou - Let me know what you think and I can try and raise a PR that enables this support.

[thinkerou]

@krmahadevan please, thanks!

[ericdriggs]

@krmahadevan Please post your changes. I could use this as well

[krmahadevan]

@thinkerou - I have raised a PR that adds support for loading protobin files from CLASSPATH

#37

@ericdriggs - My bad for the insane delay. Somehow I lost track of this. Hope the PR gets merged and you can use the changeset.