<!--
Please provide as much information as possible about what your PR aims
to do.
PRs with no description will most likely be closed until more
information is provided.
If you're planing on changing fundamental behaviour or add big new
features, please open a GitHub Issue first before starting to work on
it.
If it's not something big and you still want to contact us about it,
feel free to do so !
-->
### Problem description
https://github.com/WerWolv/ImHex/issues/1895
### Implementation description
Added code that handles streamed zstd data. It is based around the
[official
documentation](http://facebook.github.io/zstd/zstd_manual.html) and the
[example](https://github.com/facebook/zstd/blob/dev/examples/simple_decompression.c)
provided at the main zstd repo.
The loop around the non-streamed version was also removed because I
don't think it was doing anything (no `continue`s, `sourceSize` was
always being set to 0).
### Additional things
To test, I generated streamed zstd data with this python script:
```py
import io; import pyzstd;
with open("data.zstd", "wb") as f:
pyzstd.compress_stream(io.BytesIO(b'ab' * 100), f)
```
And then I ran this pattern script:
```
import std.mem;
import hex.dec;
u8 data[while(!std::mem::eof())] @ 0x00;
std::mem::Section data_sec = std::mem::create_section("data_sec");
hex::dec::zstd_decompress(data, data_sec);
```
Inspecting the section shows the correct data:
Co-authored-by: Nik <werwolv98@gmail.com>
Prior to this, at least on Linux/MacOS/etc, I guess it was not possible
to compile with Zstd included for `hex::dec::zstd_decompress()`:
Every other target lib for the decompression plugin would compile,
**except for** Zstd. Additionally, the target name `zstd` caused CMake
to not be able to find `Find(ZSTD).cmake` due to case-sensitivity
differences between Windows and Unix-based file paths, of course.
With that said, I'm not too sure if this will break building w/ Zstd on
Windows... Hopefully not 😄
