[HIPIFY][doc] Readme.md update
[HIPIFY][doc] Readme.md update

+ supported CUDA version to LLVM version correspondence table is added.
+ Test section is rewritten.
+ Windows support is added.

ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,ROCm-Developer-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP,GPUOpen-ProfessionalCompute-Tools/HIP