* Added plugin with DPC++-based predictor and objective function
* Update CMakeLists.txt
* Update regression_obj_oneapi.cc
* Added README.md for OneAPI plugin
* Added OneAPI predictor support to gbtree
* Update README.md
* Merged kernels in gradient computation. Enabled multiple loss functions with DPC++ backend
* Aligned plugin CMake files with latest master changes. Fixed whitespace typos
* Removed debug output
* [CI] Make oneapi_plugin a CMake target
* Added tests for OneAPI plugin for predictor and obj. functions
* Temporarily switched to default selector for device dispacthing in OneAPI plugin to enable execution in environments without gpus
* Updated readme file.
* Fixed USM usage in predictor
* Removed workaround with explicit templated names for DPC++ kernels
* Fixed warnings in plugin tests
* Fix CMake build of gtest
Co-authored-by: Hyunsu Cho <chohyu01@cs.washington.edu>
