Move Wasmtime for .NET to the Wasmtime repo.

This moves the Wasmtime for .NET implementation to the Wasmtime repo.

Wasmtime for .NET is a binding of the Wasmtime API for use in .NET.

crates/misc/dotnet/examples/global/global.wat

@@ -0,0 +1,22 @@
+(module
+  (import "" "print_global" (func $.print_global))
+  (import "" "global" (global $.global (mut i32)))
+  (func $run (param i32) (local $i i32)
+    loop $l1
+      call $.print_global
+      global.get $.global
+      i32.const 2
+      i32.mul
+      global.set $.global
+      local.get $i
+      i32.const 1
+      i32.add
+      local.set $i
+      local.get $i
+      local.get 0
+      i32.le_u
+      br_if $l1
+    end
+  )
+  (export "run" (func $run))
+)