Cleanup C# projects, code quality & style

New rules:
- Do not silence CA1805 any more
- Limit where we silence CA1707, CA1711, CA1720
- Enforce severity=warning for IDE0040
- Enforce Allman style braces
- Enforce naming conventions (IDE1006 is still severity=suggestion)

Fixes:
- Fix REFL045, CS1572, CS1573
- Suppress CS0618 when generating `InvokeGodotClassMethod`
- Fix indent when generating GD_constants.cs
- Temporarily silence CS1734 in generated code
- Fix a lot of naming rule violations

Misc.:
- Remove ReSharper comments for RedundantNameQualifier
- Remove suppression attributes for RedundantNameQualifier
- Remove severity=warnings for CA1716, CA1304 (already included in the level of analysis we run)

modules/mono/editor/Godot.NET.Sdk/Godot.SourceGenerators.Sample/Generic.cs

@@ -3,7 +3,7 @@
 namespace Godot.SourceGenerators.Sample
 {
     // Generic again but without generic parameters
-    partial class Generic : GodotObject
+    public partial class Generic : GodotObject
     {
         private int _field;
     }