Remove MIOpenGEMM and MIOpenTensile code

[JehandadKhan]

Both of the above GEMM backends have been deprecated and their code sits in the library still. Perhaps its prudent to just remove it and simplify the gemm backend code.

cc @junliume @atamazov

[atamazov]

@JehandadKhan Sure! I think this is https://github.com/ROCmSoftwarePlatform/MIOpen/labels/quality https://github.com/ROCmSoftwarePlatform/MIOpen/labels/urgency_normal

[atamazov]

@JehandadKhan Please assign @averinevg @DrizztDoUrden and me as well. The one who first has free time or desire will take it into work.

[DrizztDoUrden]

I'd like to do this as it will reduce my headache from fixing bazillion corner-case code paths in kernel binary serialization in solution

[averinevg]

MIOpenGEMM and MIOpenTensile leftovers were removed in #2499