[HLSL][RootSignature] Add Root Signature object manipulation options

[inbelic]

This issue is an umbrella issue to track the work required to implement the root signature related object manipulation driver options that will be implemented in clang, as described here.

Each sub-issue describes a corresponding option.

This issue is complete when all sub-issues are completed.

[inbelic]

Before any sub-issues are created it should be decided in which tool these should be implemented. Possible candidates are objcopy and related tools.

[damyanp]

Some discussion from refinement: we should think about which of these have actual use cases and be mindful of adding support for those that are used. We can always add these later when we discover requirements for it.