We have `arg.none() = nb::none()` in a lot of places but this is no
longer necessary (as of
~[2022](https://github.com/wjakob/nanobind/commit/62a23bb87b57d939e045f9c9da78a1d7235d2271)).

This is a companion to #118583, although it can be landed independently
because since #117922 dialects do not have to use the same Python
binding framework as the Python core code.

This PR ports all of the in-tree dialect and pass extensions to
nanobind, with the exception of those that remain for testing pybind11
support.

This PR also:
* removes CollectDiagnosticsToStringScope from NanobindAdaptors.h. This
was overlooked in a previous PR and it is duplicated in Diagnostics.h.

---------

Co-authored-by: Jacques Pienaar <jpienaar@google.com>

This patch adds the `#gpu.kernel_metadata` and `#gpu.kernel_table`
attributes. The `#gpu.kernel_metadata` attribute allows storing metadata
related to a compiled kernel, for example, the number of scalar
registers used by the kernel. The attribute only has 2 required
parameters, the name and function type. It also has 2 optional
parameters, the arguments attributes and generic dictionary for storing
all other metadata.

The `#gpu.kernel_table` stores a table of `#gpu.kernel_metadata`,
mapping the name of the kernel to the metadata.

Finally, the function `ROCDL::getAMDHSAKernelsELFMetadata` was added to
collect ELF metadata from a binary, and to test the class methods in
both attributes.

Example:
```mlir
gpu.binary @binary [#gpu.object<#rocdl.target<chip = "gfx900">, kernels = #gpu.kernel_table<[
    #gpu.kernel_metadata<"kernel0", (i32) -> (), metadata = {sgpr_count = 255}>,
    #gpu.kernel_metadata<"kernel1", (i32, f32) -> (), arg_attrs = [{llvm.read_only}, {}]>
  ]> , bin = "BLOB">]

```
The motivation behind these attributes is to provide useful information
for things like tunning.

---------

Co-authored-by: Mehdi Amini <joker.eph@gmail.com>

The PR adds py binding for `AsyncTokenType`