This new cmake option can take the following values
- `Intel-MKL` - Intel MKL is used for blas, fft and sparse related routines
- `FFTW/LAPACK/BLAS` - OpenBLAS for blas routines; fftw for fft routines; netlib compatible
  lapack library for lapack routines
- `Intel-MKL` is the default value of this option.
We intend to add AMD-AOCL as the third option.
To preserve the behavior provided by the old flags, USE_CPU_MKL &
USE_OPENCL_MKL, if provided(command-line/cmake-gui) will take
precedence even if `AF_COMPUTE_LIBRARY` has `FFTW/LAPACK/BLAS`.
Add back vcpkg caching mechanism. The work around we tried so far has
increased the build time too much on windows github action
Putting vcpkg under arrayfire source root or build folder is making
vcpkg think it is in manifest mode and any `vcpkg install` commands are
not doing expected standalone dependency installations.
Cannot use af_deprecate calls of USE_*_MKL flags, it cannot handle different type cmake variables