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/tests/Modules/MemoryImportBinding.wat

@@ -0,0 +1,39 @@
+(module
+  (import "" "mem" (memory 1))
+  (data (i32.const 0) "Hello World")
+  (data (i32.const 20) "\01")
+  (data (i32.const 21) "\02\00")
+  (data (i32.const 23) "\03\00\00\00")
+  (data (i32.const 27) "\04\00\00\00\00\00\00\00")
+  (data (i32.const 35) "\00\00\a0\40")
+  (data (i32.const 39) "\00\00\00\00\00\00\18\40")
+  (data (i32.const 48) "\07\00\00\00\00\00\00\00")
+  (func (export "ReadByte") (result i32)
+    i32.const 20
+    i32.load8_s
+  )
+  (func (export "ReadInt16") (result i32)
+    i32.const 21
+    i32.load16_s
+  )
+  (func (export "ReadInt32") (result i32)
+    i32.const 23
+    i32.load
+  )
+  (func (export "ReadInt64") (result i64)
+    i32.const 27
+    i64.load
+  )
+  (func (export "ReadFloat32") (result f32)
+    i32.const 35
+    f32.load
+  )
+  (func (export "ReadFloat64") (result f64)
+    i32.const 39
+    f64.load
+  )
+  (func (export "ReadIntPtr") (result i64)
+    i32.const 48
+    i64.load
+  )
+)