Fix hardcoded java dockerfile by using wildcard in copy source path

[GREENRAT-K405]

Changed the hardcoded 0.0.1-SNAPSHOT.jar with *(wildcard)

This will make sure the maintainers don't have to manually change version in dockerfile every time the concore gets an version update. This fixes #320

[GREENRAT-K405]

@pradeeban please have a look.

[GREENRAT-K405]

@pradeeban this dockerfile also lacks build stage.
We could setup the ./target/ manually but if someone wants to simply just clone the repo and get started... it lacks the build stage.

Should I work on this?

[pradeeban]

Sure, Go ahead.
concore doesn't have a Java implementation. Any code you see should be considered a toy. That is why all the obvious bugs you all are spotting in the Java implementation.

[GREENRAT-K405]

Understood! I will at least create a minimal fix.