[HLSL] Create HLSLConstantAccess pass to translate `hlsl_constant` loads

[hekota]

Create a new HLSLConstantAccess pass that will translate all load instructions in hlsl_constant address space to llvm.{dx|spv}.resource.load.cbuffer intrinsics calls. It will make use of the metadata generated in #113514 that maps the constants global variables to individual constant buffers and specified the constant buffer layout. The pass also needs to transform related getelementptr instructions to use the constant buffer layout offsets.

After the HLSLConstantAccess pass completes the constant buffer metadata is no longer needed and should be removed.