[FEA] Java bindings should connect RMM logger to slf4j

**Is your feature request related to a problem? Please describe.**
RMM can create log output which defaults to output in `rmm_log.txt`. There currently isn't a way to connect this output to the other logging output from cudf which is currently funneled through the slf4j API.

**Describe the solution you'd like**
The RMM spdlog sink should be replaced immediately after startup with a sink that can log to slf4j. This allows the user to customize at runtime how the RMM logs should be handled, whether that's sent to a file, stderr, or some other, custom logging handler. See https://github.com/rapidsai/rmm/issues/564#issuecomment-822964167 for details on how the RMM spdlog sink can be updated.

**Describe alternatives you've considered**
We could simply emit these error messages to stderr, but using slf4j would be more flexible for applications.