fix(core): Optimizes strings / .NET 5 compatibility changes (#354)

- [X] Removes some string allocations (e.g. split)
- [X] Optimizes some collections
- [X] Converts insensitive to extension methods of built-ins.
- [X] Adds ordinal (case sensitive) string helpers
- [X] Fixes conditionals for in-game commands so they use Ordinal comparisons.
- [X] Replaces ToLower.Contains with InsensitiveContains
- [X] Adds ValueStringBuilder
- [X] Implements ValueStringBuilder in a few places where it makes sense
- [X] Removes the redundant Wrap function and replaces it with an optimized version
- [X] Fixes list conversions in Utility

Closes #351

Bumps release version

Projects/Server.Tests/Tests/Buffers/ValueStringBuilderTests.cs

@@ -0,0 +1,21 @@
+using Server.Buffers;
+using Xunit;
+
+namespace Server.Tests.Buffers
+{
+    public class ValueStringBuilderTests
+    {
+        [Theory]
+        [InlineData("Admin Kamron", "Kamron", 0, 6)]
+        [InlineData("Admin Kamron", "Admin ron", 6, 3)]
+        [InlineData("Admin Kamron", "Admin", 5, 7)]
+        public void TestRemove(string original, string removed, int startIndex, int length)
+        {
+            using var sb = new ValueStringBuilder(stackalloc char[64]);
+            sb.Append(original);
+            sb.Remove(startIndex, length);
+
+            Assert.Equal(removed, sb.ToString());
+        }
+    }
+}