[REVIEW] Remove unused native deps from java library [skip-ci]

[revans2]

This removes nvstrings and nvcategory from what is packaged in the java jar. They are no longer used so we can remove them.

This also adds in packaging of libnvrtc if static linking is enabled. This is not 100% perfect as libnvrtc will do a dlopen on libnvrtc-builtins.so But it is a step in the right direction.

[GPUtester]

Please update the changelog in order to start CI tests.

View the gpuCI docs here.

[revans2]

Just to be clear I manually ran several tests to verify that nvstring and nvcategory are no longer needed by the java code.

[kuhushukla]

Curious why we need this change for this PR, or is this change also about static linking and marking dependencies as required and optional? My understanding of static linking is limited so pardon any naivety.

[revans2]

Yes so we can statically link against cudart, but nvrtc which is the runtime compiler we cannot statically link against and it is tied to the cuda release version 10.02, 10.1, etc. This copies it into the jar when we are doing static linking.

[jlowe]

It's important to note that technically libcudf.so still links against libNVCategory and libNVStrings. I get errors when I try to build libcudf.so without first building the nvstrings target. However neither string library appears in the dynamic dependencies of libcudf.so as reported by ldd.