Remove unused direct dependencies orjson, Brotli and zstandard from configuration files

[karyotakisg]

Description of the changes

As part of our ongoing research on Python dependency management we noticed a potential improvement in your project’s dependency management.

Specifically, the direct dependencies orjson, zstandard and Brotli are specified as a requirement in the base.in and base.txt files, when in reality they are not needed.

Hope this is helpful!

Best regards

Have the changes in this PR been tested?

Yes, tox was used.

[Flame442]

For brotli, aiohttp considers it an optional dependency and gains increased performance/functionality when it is installed. For orjson, discord.py considers it an optional dependency and gains increased performance parsing data from the discord API. I don't know for certain for z standard, but I imagine we have it for a similar reason as the other two. It could potentially be documented better that they are not unused dependencies.

[Jackenmen]

These are used - not by our code directly but by our dependencies. They don't get added as transitive dependencies by pip-compile because they're optional dependencies and we don't list the relevant extras they're included in as those extras don't allow for the same granularity (i.e. I can't include aiohttp[speedups] without also including aiodns, which we don't want).
Closing as invalid.