Consider tomlkit to support TOML markup

[schaefi]

Description

Hi there, first of all thanks much for anymarkup. It's a great module and I'm using it for quite some time in the KIWI
appliance builder project. Recently there was the request to also support the TOML markup for describing an image description. I added a pull request to support this using anymarkup and its toml backend. You can see the open PR here:

• Support TOML markup OSInside/kiwi#2375

As you can see it would add a new python module dependency to the toml module because that's how anymarkup
implements support for it. It all works nicely but a review comment was made stating that support for TOML has been
split into tomllib in the Python 3.11+ standard library for reading, and tomlib-w for writing.

From that perspective I'd like to ask if you would consider to support the new tomllib implementation as
alternative backend to support TOML with python 3.11+ ?

For us from the KIWI side this would be great as we don't need to add a dependency to the old toml module
and benefit from features of the new tomllib e.g style and comment preserving

Thanks much