feat: Adds .NET 7 & Arm64 support (#1229)

## BREAKING CHANGE
**Publishing for linux will no longer include runtimes**

## Major Changes
* Adds .NET 7 support.
* Adds ARM64 support (experimental).
* Changes linux support to be open-ended against anything .NET 7 supports.
* Fixes native library resolutions. (Make sure to install `dev` versions of the libraries)
* Updates README
* Adds Ubuntu 22, CentOS 8/9 Stream to CI/CD.

## TODOs:
* Update modernuo.com docs

Closes #1173
Closes #1159

Projects/Server/Collections/PooledRefQueue.cs

@@ -316,11 +316,7 @@ public ref struct PooledRefQueue<T>
     }
 
     // Increments the index wrapping it if necessary.
-#if NET7_SDK
     private void MoveNext(scoped ref int index)
-#else
-    private void MoveNext(ref int index)
-#endif
     {
         // It is tempting to use the remainder operator here but it is actually much slower
         // than a simple comparison and a rarely taken branch.