[Tracking Issue] Improve CPU backend support without CUDA

[LDY1998]

This is a tracking issue for adding CPU compilation without CUDA:

• Refactor codegen to separate GPU/CPU code generation
  Refactor codegen to separate GPU/CPU code generation #176
• Refactor Storage api to use libc for memory management instead of CUDA Host
  Refactor compilation workflow to support CPU without CUDA #189
• Add test workflow in cpu-only enivironment

[tonyzhao-jt]

Hi, when will the CPU version be available？ Looking forward to it.

[yaoyaoding]

Hi @SpringWave1, you can try it even now.

a = hidet.randn([3, 4])
b = hidet.randn([4, 3])
c = a @ b

Hidet will generate the matrix multiplication kernel and run it with CPU.
However, now our auto-scheduler only generates kernel that uses a single thread, and there is not efficient matmul schedule template. We are still working on these. The good support might come in the end of this year.