Consider using zstd from stdlib for Python >= 3.14

**Describe the solution you'd like**
Currently `aiokafka` requires the third party dependency `cramjam` for zstd support. However, since Python 3.14 the stdlib has the module `compression.zstd` (https://docs.python.org/3/library/compression.zstd.html).

**Additional context**
The change to support this should be minimal as the stdlib API is similar to cramjam's.