[DFT] Fix MKLCPU DFT backend build issue

[FMarno]

Description

Fix a build issue introduced to the MKLCPU backend. This backend is not currently supported so the tests haven't been run.
This can be reproduced with the cmake setup

cmake -GNinja -Bbuild -S. -DCMAKE_CXX_COMPILER=/opt/intel/oneapi/compiler/2023.0.0/linux/bin/icpx -DCMAKE_C_COMPILER=/opt/intel/oneapi/compiler/2023.0.0/linux/bin/icx -DMKL_ROOT=/opt/intel/oneapi/mkl/2023.0.0

since ENABLE_MKLCPU_BACKEND is defaulted to ON and when no TARGET_DOMAIN is specified it will add dft automatically.

I've also updated the README because DFT was not listed as a supported domain.

Fixes #294

Checklist

All Submissions

• Do all unit tests pass locally? Attach a log.
• Have you formatted the code using clang-format?

Bug fixes

• Have you added relevant regression tests? - NA
• Have you included information on how to reproduce the issue (either in a
  GitHub issue or in this PR)?

[FMarno]

@Rbiessy realised the issue with this solution is that we now have failing tests for the MLKCPU backend enabled. Here is a log of the test run: mklcpu_run.txt.
I decoded the return status of 3 with DftiErrorMessage and it said Intel MKL DFTI ERROR: Inconsistent configuration parameters.
I still personally believe #301 is the correct solution since the MKLCPU backend was never in a stable position to begin with.

[Rbiessy]

#291 may fix this issue with the MKLCPU backend since it is not committing the descriptor when testing that we can get and set the values.
I agree that #301 is the safest approach until the CPU backend is properly enabled.

[FMarno]

Test run - test_run.txt

[lhuot]

Thanks for the fix!