chore: cleanup & improve networking

The current network implementation has some issues that needed to be addressed. Most noticeble are:

issues with very high native memory consumption due to netty not releasing native memory instantly
issues with a lot of loaded classes that were auto generated
use of ASM which leads to issues with server implementations
rpc code generation can be noticeably improved, especially to ease the usage
and many places where the old code was just messy and could be replaced with a cleaner & easier to read version

bump the required java version for cloudnet to 22 & enable preview features.
replace the usages of ASM in code generation with the java classfile api
rewrite rpc handling & code generation completely
improve default values for settings (for example lower thread counts for packet handling)
improve chunked data transfer, prevent race conditions when querying files
use custom buffer allocator that releases native memory immediately instead of relying on GC
higher test coverage
... and many more small cleanups and improvements

Improved networking that should ease the use for external users and definitely decrease the amount of reported errors.

CloudNetService / CloudNet