hipBLAS 0.50.0 for ROCm 5.1.0

Added

• Added library version and device information to hipblas-test output
• Added --rocsolver-path command line option to choose path to pre-built rocSOLVER, as
  absolute or relative path
• Added --cmake_install command line option to update cmake to minimum version if required
• Added cmake-arg parameter to pass in cmake arguments while building
• Added infrastructure to support readthedocs hipBLAS documentation.

Fixed

• Added hipblasVersionMinor define. hipblaseVersionMinor remains defined
  for backwards compatibility.
• Doxygen warnings in hipblas.h header file.

Changed

• rocblas-path command line option can be specified as either absolute or relative path
• Help message improvements in install.sh and rmake.py
• Updated googletest dependency from 1.10.0 to 1.11.0