Transport compression support

[fgardt]

Reworks how the current payload compression is handled and adds support for transport compression.

• implement zlib-stream decompression
• implement zstd-stream decompression

Should close #693.
And unlike #1508 it concats the WS query params with & instead of ?.

#1508 had some logic to periodically resize/shrink buffers (even tho it seems like it was not hooked up to be called anywhere?) which this PR does not yet have.

[GnomedDev]

Just some initial comments, alongside this I don't think you should implement buffer resizing logic if not necessary as lowering the buffer size isn't going to lead to a noticeable memory usage improvement compared to the code complexity.

[fgardt]

zlib-stream decompression does work now.
Tested by running e01_basic_ping_bot with all gateway intents.

Trying to get zstd-stream decompression working next.

[GnomedDev]

Hmm, this looks good, just a small concern with the zstd library.

[GnomedDev]

This kind of create and init pattern is making me iffy about zstd_safe, especially not being able to find any documentation on what it possibly errors on. Is there another library for it?

[fgardt]

_{this is restating things that have been said on discord for completeness sake.}

zstd_safe is using bindings to the zstd reference implementation in C (https://github.com/facebook/zstd). The (to my knowledge) only other crate for zstd decompression that is not relying on zstd_safe in some way is ruzstd. Looking at the docs for ruzstd it does not look that nice to work with in our context at least but maybe I'm wrong about that. The performance hit compared to the C implementation is unclear, should probably be tested.

[GnomedDev]

Okay, I'm good with merging this as-is, if it has been tested.

[fgardt]

I retested the current state with e01_basic_ping_bot and all compression settings worked without any issues.