State extension: provide batch parameter updates to reflect the changes back to UI

[atsushieno]

After loading a state (or a preset), the host will have to get updated parameters so that its UI can reflect the changes.

At this moment, there is no way to "get" parameter value from a plugin (because it involved Binder messaging now, which should be improved by AAP SysEx8), and we certainly do not want to have 100+ "get parameter value" requests flooding at a time. State loading is, however, a case such a batch updates is required.

As a solution, forcing plugins that it must send parameter update notifications after loading a state, is kind of doable. But since parameter update UMPs (in sysex8) are still enormous and parsing all those feels extraneous. We could simplify it by defining another parameter "bulk dump" request.

It should also be noted that we do not always need parameter updates after loading state - an audio renderer would not need the latest parameters states. Therefore, it is not connected to "load state" operation, at plugin API wise. There should be a helper function that implements state loader to involve parameter bulk dump (optionally) so that every plugin developer (or plugin bridge developer) does not have to care about it.