Mojo: Move mojo/public/bindings to mojo/public/tools/bindings.

mojo/public/tools/bindings/generators/cpp_templates/params_definition.tmpl

 {%- import "struct_macros.tmpl" as struct_macros %}
 {%- set class_name = struct.name ~ "_Data" %}
 class {{class_name}} {
  public:
   static {{class_name}}* New(mojo::Buffer* buf) {
     return new (buf->Allocate(sizeof({{class_name}})))
         {{class_name}}();
   }
 
 {#--- Setters -#}
@@ skipping 22 matching lines @@
   {{class_name}}() {
     _header_.num_bytes = sizeof(*this);
     _header_.num_fields = 3;
   }
 
   mojo::internal::StructHeader _header_;
 {{ struct_macros.fields(struct) }}
 };
 MOJO_COMPILE_ASSERT(sizeof({{class_name}}) == {{struct.packed|struct_size}},
                     bad_sizeof_{{class_name}});