Most wanted packages for external detection

• gawk (DONE; https://github.com/spack/spack/pull/23716)
• sed (DONE; https://github.com/spack/spack/pull/25481)
• cudnn
• some of the lapacks
  • atlas
  • mkl
  • openblas?
• all of the MPIs
  • openmpi (DONE; https://github.com/spack/spack/pull/18600)
  • intel-mpi
  • mpt
  • mpich (DONE; https://github.com/spack/spack/pull/18330)
  • mvapich2 (DONE; https://github.com/spack/spack/pull/18177)
  • spectrum-api (DONE; https://github.com/spack/spack/pull/18055)
• all of the hip libraries
  • hip
  • hip-rocclr
  • hsakmt-roct
  • comgr
  • llvm-amdgpu
  • rocm-device-libs
  • rocminfo