This PR updates the YAML representation of DXContainer to support Root
Signature 1.2, this also requires updating the write logic to support
testing.

This PR is updating Root Signature YAML to use enums, this is a required
change to remove the use of to_underlying from DirectXContainer binary
file.

Closes: [#150676](https://github.com/llvm/llvm-project/issues/150676)

MC Static Samplers Representation currently depends on Object
structures. This PR removes that dependency and in order to facilitate
removing to_underlying usage in follow-up PRs.

MC Descriptor Range Representation currently depend on Object
structures. This PR removes that dependency and in order to facilitate
removing to_underlying usage in follow-up PRs.

This pr fixes some inconsistencies in behaviour of how we handle
`StaticSamplersOffset` with respect to DXC and `RootParameterOffset`.
Namely:

1. Make codegen of `RTS0` always compute the `StaticSamplersOffset`
regardless if there are any `StaticSampler`s. This is to be consistent
and produce an identical `DXContainer` as DXC.
2. Make the `StaticSamplersOffset` and `RootParametersOffset` optional
parameters in the yaml description. This means it will be used when it
is specified (which was not necassarily the case before).
3. Enforce that the provided `StaticSamplersOffset` and
`RootParametersOffset` in a yaml description match the computed value.

For more context see:
https://github.com/llvm/llvm-project/issues/155299.

Description of existing test updates updates:
- `CodeGen/DirectX/ContainerData`: Updated to codegen computed values
(previously unspecified)
- `llvm-objcopy/DXContainer`: Updated to `yaml2obj` computed values
(previously unspecified)
- `ObjectYAML/DXContainer`: Updated to `yaml2obj` computed values
(previously incorrect)
- `ObjectYAML/DXContainerYAMLTest`: Updated to `yaml2obj` computed
values (previously incorrect)

See newly added tests for testing of optional parameter functionality
and `StaticSamplersOffset` computation.

Resolves: https://github.com/llvm/llvm-project/issues/155299

This patch is refactoring Root Parameter Header in DX Container backend
to remove the usage of `to_underlying`. This requires some changes:
first, MC Root Signature should not depend on Object/DXContainer.h;
Second, we need to assume data to be valid in scenarios where it was
originally not expected, this made some tests be removed.

- Adds support for static samplers ins dxcontainer binary format.
- Adds writing logic to mcdxbc
- adds reading logic to Object
- adds tests
Closes: [126636](https://github.com/llvm/llvm-project/issues/126636)

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Co-authored-by: joaosaffran <joao.saffran@microsoft.com>

Closes:
https://github.com/orgs/llvm/projects/4/views/22?sliceBy%5Bvalue%5D=joaosaffran&pane=issue&itemId=97332852&issue=llvm%7Cllvm-project%7C126635

---------

Co-authored-by: joaosaffran <joao.saffran@microsoft.com>

As requested in a previous PR, this change moves all structs related to
RTS0 to RTS0 namespace.

---------

Co-authored-by: joaosaffran <joao.saffran@microsoft.com>