* Revert to use out-of-tree GPU driver since the performance with out-of-tree driver is better than upsteam's
* add spaces
* add troubleshooting case
* update Troubleshooting
* transfer files in DockerGuides from rst to md
* add some dividing lines
* adjust the title hierarchy in docker_cpp_xpu_quickstart.md
* restore
* switch to the correct branch
* small change
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Co-authored-by: ATMxsp01 <shou.xu@intel.com>