[HLSL] Implement resource constructor with implicit binding

[hekota]

• Implement resource constructor for implicit binding as specified in resource-constructors proposal
• Initialize resources without a register annotation (or with a space-only annotation) with a call to this constructor.
• Translate __builtin_hlsl_create_handle_from_implicit_binding Clang buildins to {dx|spv}.resource.handlefromimplicitbinding according to the implicit resource binding proposal.

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Helena Kotas (hekota)

- Implement resource constructor for implicit binding as specified in [resource-constructors proposal](https://github.com/llvm/wg-hlsl/blob/main/proposals/0025-resource-constructors.md.) - Initialize resources without a register annotation (or with a space-only annotation) with a call to this constructor. - Translate `__builtin_hlsl_create_handle_from_implicit_binding ` Clang buildins to `{dx|spv}.resource.handlefromimplicitbinding` according to the [implicit resource binding proposal](https://github.com/llvm/wg-hlsl/blob/main/proposals/0024-implicit-resource-binding.md).

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Helena Kotas (hekota)

- Implement resource constructor for implicit binding as specified in [resource-constructors proposal](https://github.com/llvm/wg-hlsl/blob/main/proposals/0025-resource-constructors.md.) - Initialize resources without a register annotation (or with a space-only annotation) with a call to this constructor. - Translate `__builtin_hlsl_create_handle_from_implicit_binding ` Clang buildins to `{dx|spv}.resource.handlefromimplicitbinding` according to the [implicit resource binding proposal](https://github.com/llvm/wg-hlsl/blob/main/proposals/0024-implicit-resource-binding.md).