Add initial igpu docs and other important fixes for 0.22

fix spelling error

memory allocator for CPU 

Failing test on INTERPRETER backend.

Add QuantizedConvolution op to ngraph core

Removed deprecated fusion type constants.

Improve PlaidML backend option debugging

Migrate from r0.23

[MLIR] Bump MLIR repo to commit 82d5084 Wed Jun 26.

Remove redundant run of FusedOpDecomposition.

Decomposition of fused ops in PlaidML backend

Remove CPURuntimeContext mkldnn primitives and workspaces assignments…

Add PlaidML Quantize & Dequantize