message: [pdsl_model] Impl MessageHandlerSelector::selector and default impl Decode
diff: @@ -69,7 +69,7 @@ impl CallData {
  }
  /// A hash to identify a called function.
  -#[derive(Copy, Clone, PartialEq, Eq)]
  +#[derive(Copy, Clone, PartialEq, Eq, Decode)]
  pub struct MessageHandlerSelector(u32);
  impl MessageHandlerSelector {
  @@ -102,7 +102,7 @@ where
  {
  /// Returns the associated handler selector.
  pub const fn selector() -> MessageHandlerSelector {
  - MessageHandlerSelector(0x0) // TODO: Specify and implement behaviour.
  + <Msg as Message>::ID
  // Should produce a hash out of a byte sequence
  // that contains signatures of the following parts:
  