[WIP] Initial AMDGPU support

[carstenbauer]

• Requires https://github.com/JuliaGPU/AMDGPU.jl/pull/471
• Requires https://github.com/JuliaGPU/AMDGPU.jl/pull/472

TODOs (at least some of them 😉)

• [x] AMD GPU CI
• [ ] memory_bandwidth_saxpy_* (runs but values are suspicious/wrong)
• [ ] p2p bandwidth

[carstenbauer]

julia> using GPUInspector, AMDGPU

julia> gpus()
4 devices:
  0: HIPDevice(name="AMD Instinct MI210", id=1) (63.984 GiB / 63.984 GiB available)
  1: HIPDevice(name="AMD Instinct MI210", id=2) (63.984 GiB / 63.984 GiB available)
  2: HIPDevice(name="AMD Instinct MI210", id=3) (63.984 GiB / 63.984 GiB available)
  3: HIPDevice(name="AMD Instinct MI210", id=4) (63.984 GiB / 63.984 GiB available)

julia> memory_bandwidth();
Memory Bandwidth (GiB/s):
 └ max: 1144.27

julia> host2device_bandwidth();
Host <-> Device Bandwidth (GiB/s):
 └ max: 17.47

(cc @lukas-mazur)