Write ribasim_version to TOML and warn in core if it is different

[visr]

Fixes #1178

At first I tried to add ribasim_version to the Python data model, but struggled to get it to write to the TOML even if it had its default values. But then I thought, when we model.write, with Ribasim Python version X, we should always set that key to X. Therefore there is no point in having it be part of the data model.

This does some hardcoded current version numbers in our test TOML files. I guess we could script a way around that, but updating the version number is a documented find and replace action already anyway, so it doesn't matter much.

The warning from the core looks like this:

┌ Warning: The Ribasim version in the TOML config file does not match the used Ribasim CLI version.
│   config.ribasim_version = "2024.2.1"
│   ribasim_version = "2024.2.0"
└ @ Ribasim d:\Ribasim\core\src\main.jl:63

Upgrade information

Add a top level key to your TOML with the Ribasim version you are using.

ribasim_version = "2024.2.1"

[Hofer-Julian]

A few small comments, apart from that ready to go from my side