Support of TOML format in addition (or in replace) to INI file format

[bagustris]

Starting from Python 3.11, tomlib and toml are shipped in standard library, meaning no need to install additional packages to read .toml file.

I found this info when reading a manual configparser (in See also:). Based on its explanation, in https://toml.io/en/, TOML format has many advantages over INI format, e.g., standardization, can read different values automatically: integer, boolean, strings (while INI only can read string only, afaik). I think this can reduce the burden of future contributor due to the large use of ast.literal_eval() to parse value in INI format.

PROS:

• standardize
• flexibility when reading configuration, meaning we can support more configuration for Nkululeko e.g., number of layers, etc.

CONS:

• minimum Python is 3.11 (current minimum is 3.9)
• need additional effort

As a backup, we can support both formats (TOML and INI) in v1.0, while give depreciation warning in the next major version (v2.0?)

[felixbur]

sounds good, but I'd rather only support one format (actually in my new projects i use hydra).
So i suggest we wait a while until 3.11 is more "normal" and then switch.