Use TOML for overrides, add some special subjects

[psvenk]

Use a TOML file to make the overrides file more human-writable, and start it with some special subjects for spring 2025.

[Alwinfy]

toml

[cjquines]

ah, toml, up there with json and yaml. my recent fascination is kdl. insert xkcd comic about standards, though the fact that toml is a python builtin these days is a plus

[dtemkin1]

the TOML decoder in the toml packager isn't able to decode arrays of mixed types, which means it can't decode eg. manual section entries. Since we're on python 3.8 and can't use the native tomllib library, we might want to use the package its based on tomli?

[psvenk]

I was hesitant to use TOML for the same reasons, but I thought it's a sufficiently established standard since tomllib exists now (see also: #81 (review)).

@dtemkin1 Good point; I'll switch to tomli version 2.0.1 (the latest supporting Python 3.7).

[dtemkin1]

Also we might want to consider creating a JSON schema for the override files, to make it easier for manual entry?

[dtemkin1]

This looks good to me! We might want to email out to UG admins and ask them to send us their special subject data soon